Date   

Re: Amateur discovery of a new moon of Jupiter

kly
 

Hi all,

While we wait for the MPC to publish the discovery, I would like share my 2003 astrometry for the three unidentified Jovian moon candidates I've found, including 'EJc0061'. Hopefully the first two could be used for linking up with other unidentified Jovian moon candidates from other epochs.

EJc0016 - Fell into a CCD gap in later observations.
     EJc0016  C2003 02 24.44984 08 55 31.59 +18 47 30.5          23.4 R      568
     EJc0016  C2003 02 24.46023 08 55 31.28 +18 47 31.7                      568
     EJc0016  C2003 02 24.47407 08 55 30.85 +18 47 33.4                      568

EJc0059 - Became too faint by March 2003.
     EJc0059  C2003 02 24.44984 08 55 28.64 +18 35 20.7          23.5 R      568
     EJc0059  C2003 02 24.46023 08 55 28.41 +18 35 21.8                      568
     EJc0059  C2003 02 24.47407 08 55 28.08 +18 35 23.2                      568
     EJc0059  C2003 02 25.49177 08 55 04.97 +18 37 15.4          23.3 R      568
     EJc0059  C2003 02 25.50699 08 55 04.63 +18 37 17.0          23.2 R      568
     EJc0059  C2003 02 25.52235 08 55 04.28 +18 37 18.7          23.4 R      568
     EJc0059  C2003 02 27.47455 08 54 21.33 +18 40 46.1          23.3 R      568
     EJc0059  C2003 02 27.48941 08 54 21.00 +18 40 47.6          23.3 R      568
     EJc0059  C2003 02 27.50426 08 54 20.68 +18 40 49.2          23.5 R      568

EJc0061 - Confirmed and submitted to the MPC.
     EJc0061  C2003 02 05.40451 09 06 02.43 +17 53 13.7          22.9 R      568
     EJc0061  C2003 02 05.47230 09 05 59.94 +17 53 25.3          23.0 R      568
     EJc0061  C2003 02 06.32329 09 05 29.77 +17 55 47.9          23.2 R      568
     EJc0061  C2003 02 06.35649 09 05 28.57 +17 55 53.6                      568
     EJc0061  C2003 02 06.38192 09 05 27.64 +17 55 58.0                      568
     EJc0061* C2003 02 24.44984 08 55 13.24 +18 41 40.9          23.2 R      568
     EJc0061  C2003 02 24.46023 08 55 12.90 +18 41 42.3                      568
     EJc0061  C2003 02 24.47407 08 55 12.47 +18 41 44.0                      568
     EJc0061  C2003 02 25.49177 08 54 40.91 +18 43 56.8          23.3 R      568
     EJc0061  C2003 02 25.50699 08 54 40.45 +18 43 58.9          23.4 R      568
     EJc0061  C2003 02 25.52235 08 54 39.96 +18 44 00.7          23.4 R      568
     EJc0061  C2003 02 27.47454 08 53 40.83 +18 48 06.9          23.5 R      568
     EJc0061  C2003 02 27.48940 08 53 40.38 +18 48 08.5          23.3 R      568
     EJc0061  C2003 02 27.50426 08 53 39.92 +18 48 10.3          23.3 R      568
     EJc0061  C2003 03 12.39596 08 48 02.60 +19 10 28.7                      568
     EJc0061  C2003 03 12.40950 08 48 02.29 +19 10 30.0                      568
     EJc0061  C2003 03 12.42303 08 48 01.99 +19 10 31.2                      568
     EJc0061  C2003 04 30.23896 08 45 01.31 +19 13 11.6                      568
     EJc0061  C2003 04 30.25994 08 45 01.59 +19 13 10.0                      568
     EJc0061  C2003 04 30.27733 08 45 01.83 +19 13 08.5                      568
[post-2003 observations truncated]

Kai (they/them)


Amateur discovery of a new moon of Jupiter

kly
 

Hi all,

I'm that amateur astronomer who recovered four of Jupiter's lost moons back in December 2020.

Lately I've been working on a rudimentary project to revisit a comprehensive Jovian moons survey by Jewitt, Sheppard and Gladman et al. in 2003, which for some reason was largely undocumented despite its fruitful result of 23 Jovian moon discoveries. For a full-scale survey of Jupiter's Hill sphere like this, the data is very much unexplored when you consider that many of the recently-discovered moons (i.e. Ersa and Valetudo) were present and clearly visible in this dataset but were not reported hitherto (I've already submitted 2003 precovery observations of the 2016–2018 moons to the MPC). To supplement this, I've created a crude map showing the positions of all known Jovian moons discovered after 1999 and the February 2003 CFHT images they appear in: https://imgur.com/a/jdTfH1p 

I decided to begin my search in a set of Feb 24 CFHT images situated eastward nearest to Jupiter (691381p, 85p, and 91p), which I expected to harbor a variety of inner progrades and outer retrogrades that may have been lost and unreported due to Jupiter's glare. I've manually checked 19 out of 36 CCDs so far and I've managed to find three unidentified moon candidates (motions within 13"–21"/hr, not listed in MPC's Natural Satellites Ephemeris Service), two of which were unrecoverable either due to their faintness or were obstructed by CCD gaps in subsequent observations. My third candidate, which I've temporarily designated 'EJc0061', happened to be present in CFHT observations on Feb 25-27 and earlier Subaru observations on Feb 05-06, establishing a 22-day arc that effectively confirms that the object is bound to Jupiter (U=10.4).

I was then able to track this moon down in later CFHT observations from Mar 12 and Apr 30. Although both images had rather mediocre seeing due to Jupiter's glare, the moon's 1-sigma ephemeris uncertainty was stringent enough (<10") for me to confidently identify it. From there on, the orbit and ephemeris quality was decent enough for me to begin searching observations beyond 2003: I found it in Subaru observations from 2005 Mar 11 (1' off its predicted position!), CFHT observations from 2010 Oct 02-30, and finally CTIO/DECam images from 2017 Mar 23-26, 2018 Apr 12-13, and May 11-12. There were no viable precovery observations of this moon, as it happened to be masked behind CCD artifacts in CFHT observations from 2001 Dec 10. For those interested, I've compiled a gallery of CFHT images of this moon at https://imgur.com/a/RW1UehA.

In the end, I measured a total of 76 observations spanning an arc of 15.26 years (5,575 days). The orbit of this Jovian moon is now well-secured for decades to come, so I hereby present to you: Jupiter's 80th moon, EJc0061 = S/2003 J 24 (provisional designation pending)!

   Perijove 2021 Jan 19.320884 +/- 0.0161 TT =  7:42:04 (JD 2459233.820884)
Epoch 2021 Jul  5.0 TT = JDT 2459400.5                        Find_Orb
M  86.48445599 +/- 0.008            (J2000 ecliptic)
n   0.51886797 +/- 1.24e-6          Peri.  169.25127 +/- 0.006
a   0.15102114 +/- 2.42e-7          Node   289.08642 +/- 0.0023
e   0.1681198 +/- 7.09e-6           Incl.  163.42428 +/- 0.0010
P   1.90/693.81d           H 16.4   G  0.15   U  3.8  
q 0.12563148 +/- 9.75e-7    Q 0.17641079 +/- 1.25e-6
From 76 observations 2003 Feb. 5-2018 May 12; mean residual 0".16

Residuals in arcseconds: 
030205 568  .00   .13-    101002 568  .05-  .04+    180412 W84  .04+  .05-    
030205 568  .29-  .06+    101002 568  .08-  .24-    180413 W84  .05+  .14-    
030206 568  .13-  .14-    101009 568  .03-  .08-    180413 W84  .17+  .18-    
030206 568  .07-  .07-    101009 568  .02+  .09-    180413 W84  .08+  .06-    
030206 568  .15-  .04+    101009 568  .04+  .11-    180511 W84  .01+  .28+    
030224 568  .06-  .01-    101009 568  .08-  .13-    180511 W84  .14-  .24+    
030224 568  .18-  .04+    101009 568  .06-  .15-    180511 W84  .01+  .11+    
030224 568  .01-  .05-    101030 568  .11-  .01-    180511 W84  .05-  .12+    
030225 568  .11-  .19+    101030 568  .04-  .21-    180511 W84  .07-  .38+    
030225 568  .13+  .37+    101030 568  .18+  .10-    180511 W84  .12+  .25+    
030225 568  .01-  .23+    170323 W84  .06-  .01+    180511 W84  .01-  .11+    
030227 568  .18-  .04+    170323 W84  .07-  .01-    180511 W84  .01-  .27+    
030227 568  .15-  .15-    170324 W84  .11-  .05+    180511 W84  .14-  .03+    
030227 568  .27-  .15-    170324 W84  .03+  .32-    180511 W84  .24-  .02-    
030312 568  .11-  .02+    170324 W84  .13-  .25+    180512 W84  .10-  .10+    
030312 568  .13-  .21+    170326 W84  .03+  .16-    180512 W84  .20-  .09+    
030312 568  .01-  .31+    170326 W84  .18+  .12-    180512 W84  .16-  .09+    
030430 568  .68+  .11+    170326 W84  .02+  .24+    180512 W84  .12-  .18+    
030430 568  .48+  .04+    170326 W84  .00   .03-    180512 W84  .23-  .08+    
030430 568  .42+  .17-    170326 W84  .02-  .18-    180512 W84  .25-  .03+    
050311 568  .12-  .12-    170326 W84  .04-  .04-    180512 W84  .22-  .03+    
050311 568  .06-  .12-    170326 W84  .06-  .02-    180512 W84  .17-  .12+    
050311 568  .10+  .05+    170326 W84  .07+  .02+    180512 W84  .13-  .22+    
101002 568  .08-  .08+    170326 W84  .05+  .06+    180512 W84  .21+  .08+    
101002 568  .12-  .10+    180412 W84  .19+  .07-    
101002 568  .16-  .12+    180412 W84  .18+  .11-    

I'm proud to say that this is the first planetary moon discovered by an amateur astronomer! Other than that, there really isn't anything remarkable about this Jovian moon—it's just a typical member of the retrograde Carme group. Its Rmag range of 23.2–23.5 falls just below Ashton et al.'s proposed completion limit of Rmag=23.2 for known retrograde Jovian moons.

As of writing this, the Minor Planet Center has not published my astrometry yet. For this reason, I shall withhold my astrometry unless obliged privately. In the meantime, I will continue my hunt for unidentified Jovian moons in the February 2003 dataset, so stay tuned for additional Jovian moon discoveries by me in the next coming months! (and I'd highly appreciate some help from professionals who are willing to share their proprietary astrometry of Jovian moon candidates from the 2003 survey.)

Lastly, I thank my friends Sam Deen, Elvis Mendes, Andy Roberts, and Dreigorich for sticking with me during the entire process of discovering this moon. Furthermore, I also thank Stephen Gwyn et al. for the CADC's SSOIS, Pierre Fernique for Aladin Sky Atlas, and Bill Gray for Find_Orb. This discovery would not have been possible without their tools.

Kai (they/them)


Re: 2014 UN271: cometary activity

Sam Deen
 

Hi all,

A quick elaboration: The reason for occultations being inaccurate in the past is that Occult cannot predict/model orbit perturbations, which this object has quite a few of. For these reasons, I had to simulate occultations a few months at a time with different epoch orbits just to be accurate to a couple thousand kilometers. I have now done a finer pass with the epoch given as the two predicted occultation events to determine exactly where they will appear:

2021 Sep 18 event: https://i.imgur.com/Lkq6oo5.png (Tasmania, with 1-sigma lines passing over most of Australia's eastern coast. In reality these 0.033" lines will be much smaller, because the uncertainty is mostly in the direction of motion, not perpindicular as depicted here. With that in mind, I think only observers in Tasmania and the Australian coast have a chance of observing it.)

2023 Sep 20 event: https://i.imgur.com/yRlUW83.png (passes over Antarctica and pretty much nothing else, making this event a no-go. Again, the uncertainty is smaller in reality than it appears here.)

It looks like the 2021 event is the only event in the next >2 years we have any chance at all of observing. Perhaps at least theoretically thinking of the logistics of an observation campaign in Tasmania/Melbourne/Sydney?

~Sam

On Wednesday, June 30, 2021, 4:15:52 PM PDT, Sam Deen via groups.io <planetaryscience@...> wrote:


Hi all,

I agree entirely that it's premature to predict occultations more than a year or two in advance now - I've just made an optimized orbit with some more specific formal uncertainties for each observation to reduce the position uncertainty - the uncertainty at the current moment is around +/- 0.022 arcseconds (320 kilometers) - about 4 times its nominal radius of 85 kilometers (A=0.05). It will peak around +/- 0.044'' (620 km) in December of this year, before actually reaching an even lower minimum of +/- 0.014'' (~200 km) by April 2022. For meaningful predictions in the near future I would consider 0.030'' an upper limit - between 390 and 440 km / 4.6-5.2 radii - giving the average 1-sigma observer a ~20% chance of spotting an occultation.

With this in mind, I've manually derived a formal list of upcoming appulses, with associated uncertainties, maps, circumstances, and other assorted info. All of these were manually validated:

TYPE          DATE                                    STAR                             STAR MAG       PATH DETAILS                                                           STAR VISIBLE FROM                                                                     CHART
APPULSE: 2021/07/10 07:55            |     UCAC4 191-002484   |     V=13.1     |     closest approach: 0.82 (+/- 0.023) arcseconds     |     visible: South America                                                                |    https://i.imgur.com/VcMxRma.png
APPULSE: 2021/08/10 00:43            |     UCAC4 183-002452   |     V=12.8     |     closest approach: 0.55 (+/- 0.025) arcseconds     |     visible: Sub-Saharan Africa, far southern Argentina/Chile          |    https://i.imgur.com/IG6GC8w.png
APPULSE: 2022/04/24 21:12            |     TYC 8484-00451-1     |     V=10.9     |     closest approach: 1.97 (+/- 0.014) arcseconds     |     visible: Argentina, Southern Brazil, Western Australia               |    https://i.imgur.com/vIoLz9l.png
APPULSE: 2023/03/28 10:28            |     UCAC4 162-002342   |     V=15.4     |     closest approach: 0.79 (+/- 0.012) arcseconds     |     visible: Australia, New Zealand, far southern Argentina/Chile    |    https://i.imgur.com/KBC3FQe.png
APPULSE: 2023/05/19 05:32            |     UCAC4 164-002766   |     V=13.9     |     closest approach: 0.26 (+/- 0.027) arcseconds     |     visible: New Zealand, far southern Argentina/Chile                    |    https://i.imgur.com/9x4lXer.png

Unfortunately there are no predicted occultations in these timespans when the uncertainty is less than 30 mas - and the closest appulse (2023) happens during astronomical twilight for the only place that can see it at a high altitude. However! There IS one occultation opportunity in the next couple years - across western Australia - where the uncertainty is higher, but should be easy to narrow down in the coming couple of months:

TYPE          DATE                                    STAR                             STAR MAG                                  PATH DETAILS                                                                                             STAR VISIBLE FROM                                                                     CHART
OCCULTATION: 2021/09/18 16:46    |     UCAC4 172-002357   |    V=15.9      |    PATH: northwestern Australia, West Papua (+/- 0.033 arcseconds / 464 km)    |    visible: Australia, New Zealand, Indonesia                                  |    https://i.imgur.com/tRkO2Rm.png

The maximum duration will be 6.2 seconds (depending on diameter) - the main problem is that the target star is magnitude 15.9, so would not be small-telescope accessible at all. To add to this, the part of australia it passes over isn't particularly densely populated, and most of the +1 sigma would be unobservable over sea, unless there are large telescope observers in Timor, Sumba, Flores, or the Maluku Islands.

Very uncertain occultations:
TYPE          DATE                                    STAR                             STAR MAG                                  PATH DETAILS                                                                                             STAR VISIBLE FROM                                                                     CHART
OCCULTATION: 2023/09/20 04:59    |     UCAC4 132-003086   |    V=16.0      |    PATH: Chile, Argentina, Brazil (+/- 0.100 arcseconds / 1227 km)                       |    visible: South America, western Africa                                        |    https://i.imgur.com/y8Fdc5I.png

Beyond this point the uncertainty grows too large to be practical to predict. These are the only two possible occultations before then - I invite others to double check these events for themselves as well to confirm or disprove the accuracy of my solutions. Below is attached the existing observations list with the associated uncertainties I used added on - a combination of formal uncertainties, and assumed "worst case scenario" ones.

~Sam

    CK14UR1N KC2014 08 14.59978001 42 23.996-35 36 37.600.13 0.1322.58GVEM083F51
    CK14UR1N OC2014 08 28.60113601 41 25.15 -36 02 11.8 0.07 0.0722.1 rVEM083568
    CK14UR1N OC2014 08 28.60381801 41 25.15 -36 02 12.2 0.18 0.1823.6 uVEM083568
    CK14UR1N OC2014 08 28.60641901 41 25.11 -36 02 12.4 0.07 0.0723.0 gVEM083568
    CK14UR1N OC2014 08 28.60906401 41 25.10 -36 02 12.6 0.07 0.0721.7 iVEM083568
    CK14UR1N OC2014 08 28.61174301 41 25.09 -36 02 13.0 0.07 0.0722.2 rVEM083568
    CK14UR1N*-C2014 10 20.29435 01 34 35.019-37 14 46.140.07 0.0722.49rVEM083W84
    CK14UR1N -C2014 11 04.12204 01 32 21.029-37 23 21.140.07 0.0721.97zVEM083W84
    CK14UR1N -C2014 11 15.25191 01 30 47.039-37 25 39.200.07 0.0722.43zVEM083W84
    CK14UR1N -C2014 11 18.23559 01 30 23.425-37 25 40.010.07 0.0722.12rVEM083W84
    CK14UR1N -C2014 11 18.23835 01 30 23.407-37 25 39.980.07 0.0722.15iVEM083W84
    CK14UR1N -C2014 11 27.22148 01 29 17.583-37 24 12.510.07 0.0722.71gVEM083W84
    CK14UR1N -C2014 12 11.11568 01 27 54.830-37 17 49.640.07 0.0721.94iVEM083W84
    CK14UR1N -C2015 01 09.10701 01 26 35.324-36 51 38.750.07 0.0722.80zVEM083W84
    CK14UR1N KC2015 08 11.61298001 47 05.427-37 26 12.910.13 0.1321.87GVEM083F51
    CK14UR1N -C2015 08 17.35747 01 46 47.505-37 37 39.810.07 0.0722.23rVEM083W84
    CK14UR1N -C2015 08 17.35883 01 46 47.517-37 37 39.890.07 0.0722.55gVEM083W84
    CK14UR1N -C2015 08 24.34452 01 46 18.605-37 51 28.610.07 0.0722.62gVEM083W84
    CK14UR1N -C2015 09 02.37787 01 45 30.196-38 08 52.300.07 0.0722.21YVEM083W84
    CK14UR1N -C2015 09 13.39051 01 44 15.863-38 28 51.620.07 0.0721.95iVEM083W84
    CK14UR1N -C2015 10 06.27435 01 40 59.774-39 03 19.840.07 0.0722.01zVEM083W84
    CK14UR1N -C2015 11 20.22851 01 33 55.078-39 29 32.570.07 0.0722.33zVEM083W84
    CK14UR1N -C2015 11 20.23556 01 33 55.010-39 29 32.480.07 0.0722.13iVEM083W84
    CK14UR1N -C2016 01 11.09386 01 29 57.738-38 50 26.060.07 0.0722.13rVEM083W84
    CK14UR1N -C2016 01 11.09524 01 29 57.729-38 50 25.960.07 0.0722.89gVEM083W84
    CK14UR1N  C2016 08 09.58536001 52 24.356-39 29 37.720.13 0.1322.16GVEM083F51
    CK14UR1N  C2016 08 09.59528201 52 24.325-39 29 39.110.13 0.1322.13GVEM083F51
    CK14UR1N -C2016 10 01.29899 01 46 40.180-41 11 31.780.07 0.0721.65rVEM083W84
    CK14UR1N -C2016 10 01.30036 01 46 40.173-41 11 32.000.07 0.0721.96gVEM083W84
    CK14UR1N -C2016 10 03.31546 01 46 20.177-41 14 24.530.07 0.0721.91rVEM083W84
    CK14UR1N -C2016 10 03.31682 01 46 20.167-41 14 24.590.07 0.0722.56gVEM083W84
    CK14UR1N KC2017 08 13.57144901 58 27.697-41 56 20.770.13 0.1321.81GVEM083F51
    CK14UR1N KC2017 08 14.58512301 58 24.711-41 58 44.070.13 0.1321.49GVEM083F51
    CK14UR1N KC2017 09 08.55424701 56 09.883-42 55 16.280.13 0.1321.76GVEM083F51
    CK14UR1N KC2017 09 30.42187801 52 49.635-43 36 32.720.13 0.1322.02GVEM083F51
    CK14UR1N -C2017 10 15.27208 01 50 05.746-43 57 07.300.07 0.0721.97gVEM083W84
    CK14UR1N -C2017 10 15.33777 01 50 04.988-43 57 11.800.07 0.0721.23zVEM083W84
    CK14UR1N -C2017 10 15.33915 01 50 04.970-43 57 11.890.07 0.0721.63rVEM083W84
    CK14UR1N KC2017 10 29.35825001 47 22.733-44 09 45.250.13 0.1321.54GVEM083F51
    CK14UR1N KC2017 11 06.33049701 45 51.862-44 13 42.340.13 0.1322.08GVEM083F51
    CK14UR1N KC2017 12 11.25003001 40 25.195-44 04 24.940.13 0.1321.53GVEM083F51
    CK14UR1N -C2017 12 15.18042 01 39 59.837-44 00 56.400.07 0.0722.04rVEM083W84
    CK14UR1N -C2017 12 15.18181 01 39 59.824-44 00 56.380.07 0.0722.44gVEM083W84
    CK14UR1N -C2018 10 21.24337 01 55 54.039-46 47 14.940.07 0.0721.60YVEM083W84
    CK14UR1N -C2018 10 27.17859 01 54 38.204-46 52 42.840.07 0.0721.43zVEM083W84
    CK14UR1N -C2018 11 08.23513 01 52 05.914-46 59 29.070.07 0.0721.63rVEM083W84
    CK14UR1N -C2018 11 08.23651 01 52 05.899-46 59 29.100.07 0.0721.57iVEM083W84
    CK14UR1N -C2018 11 08.23789 01 52 05.884-46 59 29.050.07 0.0722.22gVEM083W84
    CK14UR1N KC2019 08 19.59829602 14 55.242-47 31 52.430.13 0.1320.30GVEM083F51
    CK14UR1N  C2019 08 29.56986902 14 08.352-47 59 21.630.13 0.1320.58GVEM083F51
    CK14UR1N  C2019 08 29.58523402 14 08.234-47 59 24.180.13 0.1320.66GVEM083F51
    CK14UR1N  C2019 08 29.59292102 14 08.226-47 59 25.210.13 0.1320.52GVEM083F51
    CK14UR1N KC2021 06 22.13538 02 35 28.86 -51 07 43.1 0.10 0.10      VEM083L81
    CK14UR1N KC2021 06 22.16834 02 35 29.32 -51 07 47.8 0.10 0.1019.6 GVEM083L81
    CK14UR1N  C2021 06 22.16880502 35 29.32 -51 07 47.7 0.18 0.1819.8 GVEM083K93
    CK14UR1N  C2021 06 22.17258202 35 29.36 -51 07 48.5 0.18 0.1819.9 GVEM083K93
    CK14UR1N  C2021 06 22.17636102 35 29.38 -51 07 48.9 0.18 0.1819.9 GVEM083K93
    CK14UR1N  C2021 06 22.18014202 35 29.47 -51 07 49.2 0.18 0.1819.6 GVEM083K93
On Tuesday, June 29, 2021, 8:16:52 PM PDT, Marshall Eubanks <tme@...> wrote:


On 2021-06-29 11:32, Bill J. Gray wrote:
> Agreed on the unlikeliness of getting measurable non-gravs.
> (With caveats below.)
>
>    Carlos' list is extremely unlikely to prove specifically
> correct.  But it does suggest that we'll get a decent number of
> occultation opportunities over the coming years (just not of
> those specific stars).  We don't know _which_ stars yet or
> where the paths will be on the earth,  but we should get
> roughly the number of opportunities shown in his list.

If there is to be a mission to UN271, the best rendezvous time for a
flyby is  near the time of ecliptic passage, August 8, 2033, out at 11.9
AU at

Minimum energy orbits for a direct trajectories to UN271 exist, with one
launch window per year for the rest of this decade. These minimum energy
trajectories for launches up through 2029 _all_ flyby UN271
within 2 weeks of the time of its passage through the ecliptic plane. 
All of these opportunities from 2022-2029 have characteristic energies
(C_{3})  < 150 km^2/s^2, substantially less than the C_{3} of 170
km^2/s^2 required for the New Horizons probe to Pluto.

Based on a series of discussions with people who might actually launch
such a probe, I think that the 2026 window (which peaks on 2026-10-07)
is likely to be the earliest launch opportunity.

If such a mission goes forward, it would obviously be good if there were
occultation estimates of the orbit and object size and shape from  the
2024/2025 period. That (unfortunately for Northern Hemisphere observers)
will be at declinations of ~ -70 degrees.

Regards
Marshall


>
>    The first few will probably require the traditional IOTA
> method of saying "the uncertainty is several times the width
> of the ground track,  so let's get a heck of a lot of observers
> and/or put down temporary remote stations and figure that
> somebody will be in the right place."  As Brian says,  we
> might see some interesting photometric results as the star
> passes through the coma,  so even the near-miss stations might
> tell us something.
>
>    While we can't say much about specific occultations in 2028
> (start of Carlos' list),  we could make a multiple path width
> prediction for a "near-term" occultation,  much as was done
> for (486958) Arrokoth = 2014 MU69 = Ultima Thule before New
> Horizons visited it.  As with that object,  we'd quite likely
> have a failed effort or two before getting lucky.  (Though
> maybe not.  This object is about three times bigger than
> Arrokoth and half as far away.)
>
>    Depending on when it happened,  an occultation by a 100-km
> nucleus would last a minimum of about three seconds.  So
> it'd be long enough to get a decent size estimate.
>
>    The other value of occultations would be to really nail down
> the position of the object : "it was over the following star
> at exactly the following time,  and we know exactly where that
> star was because we have Gaia astrometry for it."  This has
> a couple of knock-on effects.  Give me a few such data points,
> and we'll have a much better orbit so that further occultation
> predictions will _not_ have multi-path-width uncertainties.
> And we might end up with a good enough orbit (very good
> astrometry over a couple of decades) so that very subtle
> effects,  such as non-gravs,  really _could_ be determined,
> even for such an enormous object.  In which case,  we might get
> a decent mass measurement after all.
>
>    For Arrokoth,  we started from Hubble astrometry... which,
> sadly,  may not happen this time.  But perhaps Gaia can get
> some data.
>
> -- Bill
>
> On 6/29/21 9:57 AM, Marshall Eubanks wrote:
>> On 2021-06-28 21:01, P. Clay Sherrod wrote:
>>> Personally it is my opinion that this far out, with so many unknown
>>> parameters still considered as variable factors for this unusual
>>> object, predicting occultations – unless in the immediate time frame
>>> – is unreliable and meaningless.  I believe that we are going to see
>>> some changes in orbital parameters of 2014 UN271 from both
>>> gravitational and non-gravitational forces in coming  months as the
>>> objects covers more space.  There is no reason for any of us to be
>>> planning occultation observations predicted for 2028 and 2029 at this
>>> time.
>>
>>
>> I fully agree. After July of 2024 the current UN271 ephemeris error
>> exceeds 1 Earth diameter, and there is clearly no reason to plan
>> anything at present for that period or after.
>>
>> The real question to me for now is, should money be raised to support
>> an occultation campaign in the Southern hemisphere in the next few
>> years?
>>
>> I would be very surprised if a 100 km body shows non-gravitational
>> forces visible with conventional optical astrometry. A 100 km body
>> will have 100 times the mass/area ratio of a 1 km body of the same
>> density.
>>
>> The highest mass determined from NG forcing in
>> https://academic.oup.com/mnras/article/393/1/192/1083616
>> is 4 x 10^14 kg or 1000 times smaller than the mass predicted for
>> UN271 with a 100 km diameter and a density of 0.4 gm/cm^3.
>>
>> However, if NG motions could be detected by occultation at the mas
>> level, I think that there _would_ be a decent chance of determining
>> the mass of UN271 from its NG forcing.
>>
>> Regards
>> Marshall
>>
>>>
>>> Dr. Clay
>>> Arkansas Sky Observatories
>>> www.arksky.org
>>> Petit Jean Mountain
>>> MPC H41 / MPC H43 / MPC H45
>>> .....serving astronomical sciences since 1971
>>>
>>> -----------------
>>>
>>> From: Sam Deen via groups.io
>>> Sent: Monday, June 28, 2021 7:53 PM
>>> To: mpml@groups.io ; Carlos Perelló
>>> Subject: Re: {MPML} 2014 UN271: cometary activity
>>>
>>> Hi Carlos,
>>>
>>> I'm not sure those are particularly accurate - at least, not enough
>>> for a particularly meaningful prediction. I think that this is more
>>> of
>>> a problem with occult than the orbit uncertainty, but for instance on
>>> 2028-10-05 14:40.8 find_orb records the comet as being at 10 59
>>> 13.715
>>> -61 58 11.58 which is several arcminutes from where this supposed
>>> occultation takes place. While I maintain that occultations are
>>> practically visible (and admittedly don't understand Larry's interest
>>> in discounting them unconditionally) I don't think they will be
>>> practical to predict with such an unusual orbit with Occult.
>>>
>>> ~Sam
>>>
>>> On Monday, June 28, 2021, 5:48:36 PM PDT, Carlos Perelló
>>> <rigilk436@...> wrote:
>>>
>>> I forgot to say the list is filtered by StarMag <12.6. Obviously at
>>> this time the predictions are very preliminary.
>>> Literally from the Help File of Occult: Note that the diameter is
>>> arbitrarily set at 10km, and the positional uncertainty is set at 3".
>>>
>>> Regards,
>>> Carlos
>>>
>>> El 24/06/2021 a las 13:11, Carlos Perelló escribió:
>>>
>>>>
>>>
>>> Using Occult, these are the occultations calculated until 2035:
>>>
>>>      Global summary of events - sorted by Date
>>>
>>>      Date       U.T.    Diameter   Durn  Star  Mag-Drop Elon  %
>>> Star         d Rely        Planet           Min        Moon     § ?
>>>  R.A. (J2000)  Dec.            Rec
>>>    y   m  d    h   m     km   "   sec/m   mag   V    R     o Ill
>>> No.            <1.4     No Name              D   Error Dist ill  ?
>>> h  m   s      o  '   "           #
>>> 2028 Dec  5   14 40.8    10 0.001  0.55s 12.3  8.2  8.6   69    
>>> UCAC4
>>> 140-057616 s 0.85      0 C/2014 UN271 (Be 1.28 ±4.08   89  86      10
>>> 58 27.269 -62  2 45.99         0
>>> 2028 Dec 17    9 15.7    10 0.001  0.62s 12.1  8.5  8.6   74    
>>> UCAC4
>>> 137-051856 s 4.05      0 C/2014 UN271 (Be 0.94 ±4.05   82   2      10
>>> 59 19.973 -62 36 36.98         1
>>> 2029 Jan  1    4 45.9    10 0.001  0.69s 12.6  7.9  8.1   81    
>>> UCAC4
>>> 134-047703 s 0.80      0 C/2014 UN271 (Be 5.14 ±4.00   96 100      10
>>> 58 10.418 -63 14  0.21         2
>>> 2029 Jan 31    4 18.6    10 0.001  0.59s 11.3  9.1  9.4   96     TYC
>>> 8965-01100-1 s 0.75      0 C/2014 UN271 (Be 4.47 ±3.90   75  99
>>> 10 48 24.876 -63 53 48.38         3
>>> 2029 Feb  3   17 51.4    10 0.001  0.56s 12.1  8.4  8.7   98    
>>> UCAC4
>>> 131-040285 s 0.80      0 C/2014 UN271 (Be 6.44 ±3.88   57  74      10
>>> 46 42.995 -63 54  2.93         4
>>>
>>> 2029 Dec 29   10 30.9    10 0.001  0.96s  9.7 10.5 10.3   80    
>>> UCAC4
>>> 193-062412 w 11.1      0 C/2014 UN271 (Be 3.60 ±3.84   43  38      11
>>> 42 34.634 -51 35 50.30         5
>>> 2029 Dec 29   11  7.6    10 0.001  0.94s 11.3  9.0  8.7   80    
>>> UCAC4
>>> 193-062409 w 0.95      0 C/2014 UN271 (Be 3.92 ±3.84   43  38      11
>>> 42 33.976 -51 35 52.60         6
>>> 2030 Jan  1   10  7.4    10 0.001   2.1s 10.7  9.5 10.4   82    
>>> UCAC4
>>> 192-059604 v 1.05      0 C/2014 UN271 (Be 6.15 ±3.83   58  10      11
>>> 42 27.748 -51 41 17.99         7
>>> 2032 Dec  5   20 30.3    10 0.001  0.63s 12.4  8.1  8.3   60    
>>> UCAC4
>>> 384-061530 s 1.05      0 C/2014 UN271 (Be 0.01 ±4.08   98  11      12
>>> 42 35.336 -13 13 18.53         8
>>> 2032 Dec 23    3 55.7    10 0.001  1.03s 12.0  8.4  8.7   77    
>>> UCAC4
>>> 385-061483 s 1.35      0 C/2014 UN271 (Be 0.41 ±3.99   32  66      12
>>> 45  2.980 -13  2 35.43         9
>>>
>>> 2033 Feb  2   22 47.8    10 0.001  0.56s 12.3  8.1  8.4  119    
>>> UCAC4
>>> 391-057575 s 4.20      0 C/2014 UN271 (Be 2.88 ±3.78  162  13      12
>>> 44 16.057 -11 51 12.27        10
>>> 2035 May 17   10 40.8    10 0.001  0.53s 11.0 10.3 10.6  126     TYC
>>> 1449-00435-1 s 1.00      0 C/2014 UN271 (Be 0.47 ±4.41   18  80
>>> 12 48 17.694  15 55 10.51        11
>>>
>>> Regards,
>>> Carlos
>>>
>>> El 24/06/2021 a las 12:41, andrew_j_walker via groups.io escribió:
>>>
>>>>
>>>
>>> Now we have a comet circular
>>> https://www.minorplanetcenter.net/mpec/K21/K21M83.html
>>>
>>> Nice work with the extra observations from F51 and 568, and in the
>>> last few days!
>>> Andrew
>>>
>>>
>>>
>>> Links:
>>> ------
>>> [1] https://groups.io/g/mpml/message/36525
>>> [2] https://groups.io/mt/83710102/2048683
>>> [3] https://groups.io/g/mpml/post
>>> [4] https://groups.io/g/mpml/editsub/2048683
>>> [5] https://groups.io/g/mpml/unsub
>>
>>
>>
>>
>>
>
>
>






Re: 2014 UN271: cometary activity

Sam Deen
 

Hi all,

I agree entirely that it's premature to predict occultations more than a year or two in advance now - I've just made an optimized orbit with some more specific formal uncertainties for each observation to reduce the position uncertainty - the uncertainty at the current moment is around +/- 0.022 arcseconds (320 kilometers) - about 4 times its nominal radius of 85 kilometers (A=0.05). It will peak around +/- 0.044'' (620 km) in December of this year, before actually reaching an even lower minimum of +/- 0.014'' (~200 km) by April 2022. For meaningful predictions in the near future I would consider 0.030'' an upper limit - between 390 and 440 km / 4.6-5.2 radii - giving the average 1-sigma observer a ~20% chance of spotting an occultation.

With this in mind, I've manually derived a formal list of upcoming appulses, with associated uncertainties, maps, circumstances, and other assorted info. All of these were manually validated:

TYPE          DATE                                    STAR                             STAR MAG       PATH DETAILS                                                           STAR VISIBLE FROM                                                                     CHART
APPULSE: 2021/07/10 07:55            |     UCAC4 191-002484   |     V=13.1     |     closest approach: 0.82 (+/- 0.023) arcseconds     |     visible: South America                                                                |    https://i.imgur.com/VcMxRma.png
APPULSE: 2021/08/10 00:43            |     UCAC4 183-002452   |     V=12.8     |     closest approach: 0.55 (+/- 0.025) arcseconds     |     visible: Sub-Saharan Africa, far southern Argentina/Chile          |    https://i.imgur.com/IG6GC8w.png
APPULSE: 2022/04/24 21:12            |     TYC 8484-00451-1     |     V=10.9     |     closest approach: 1.97 (+/- 0.014) arcseconds     |     visible: Argentina, Southern Brazil, Western Australia               |    https://i.imgur.com/vIoLz9l.png
APPULSE: 2023/03/28 10:28            |     UCAC4 162-002342   |     V=15.4     |     closest approach: 0.79 (+/- 0.012) arcseconds     |     visible: Australia, New Zealand, far southern Argentina/Chile    |    https://i.imgur.com/KBC3FQe.png
APPULSE: 2023/05/19 05:32            |     UCAC4 164-002766   |     V=13.9     |     closest approach: 0.26 (+/- 0.027) arcseconds     |     visible: New Zealand, far southern Argentina/Chile                    |    https://i.imgur.com/9x4lXer.png

Unfortunately there are no predicted occultations in these timespans when the uncertainty is less than 30 mas - and the closest appulse (2023) happens during astronomical twilight for the only place that can see it at a high altitude. However! There IS one occultation opportunity in the next couple years - across western Australia - where the uncertainty is higher, but should be easy to narrow down in the coming couple of months:

TYPE          DATE                                    STAR                             STAR MAG                                  PATH DETAILS                                                                                             STAR VISIBLE FROM                                                                     CHART
OCCULTATION: 2021/09/18 16:46    |     UCAC4 172-002357   |    V=15.9      |    PATH: northwestern Australia, West Papua (+/- 0.033 arcseconds / 464 km)    |    visible: Australia, New Zealand, Indonesia                                  |    https://i.imgur.com/tRkO2Rm.png

The maximum duration will be 6.2 seconds (depending on diameter) - the main problem is that the target star is magnitude 15.9, so would not be small-telescope accessible at all. To add to this, the part of australia it passes over isn't particularly densely populated, and most of the +1 sigma would be unobservable over sea, unless there are large telescope observers in Timor, Sumba, Flores, or the Maluku Islands.

Very uncertain occultations:
TYPE          DATE                                    STAR                             STAR MAG                                  PATH DETAILS                                                                                             STAR VISIBLE FROM                                                                     CHART
OCCULTATION: 2023/09/20 04:59    |     UCAC4 132-003086   |    V=16.0      |    PATH: Chile, Argentina, Brazil (+/- 0.100 arcseconds / 1227 km)                       |    visible: South America, western Africa                                        |    https://i.imgur.com/y8Fdc5I.png

Beyond this point the uncertainty grows too large to be practical to predict. These are the only two possible occultations before then - I invite others to double check these events for themselves as well to confirm or disprove the accuracy of my solutions. Below is attached the existing observations list with the associated uncertainties I used added on - a combination of formal uncertainties, and assumed "worst case scenario" ones.

~Sam

    CK14UR1N KC2014 08 14.59978001 42 23.996-35 36 37.600.13 0.1322.58GVEM083F51
    CK14UR1N OC2014 08 28.60113601 41 25.15 -36 02 11.8 0.07 0.0722.1 rVEM083568
    CK14UR1N OC2014 08 28.60381801 41 25.15 -36 02 12.2 0.18 0.1823.6 uVEM083568
    CK14UR1N OC2014 08 28.60641901 41 25.11 -36 02 12.4 0.07 0.0723.0 gVEM083568
    CK14UR1N OC2014 08 28.60906401 41 25.10 -36 02 12.6 0.07 0.0721.7 iVEM083568
    CK14UR1N OC2014 08 28.61174301 41 25.09 -36 02 13.0 0.07 0.0722.2 rVEM083568
    CK14UR1N*-C2014 10 20.29435 01 34 35.019-37 14 46.140.07 0.0722.49rVEM083W84
    CK14UR1N -C2014 11 04.12204 01 32 21.029-37 23 21.140.07 0.0721.97zVEM083W84
    CK14UR1N -C2014 11 15.25191 01 30 47.039-37 25 39.200.07 0.0722.43zVEM083W84
    CK14UR1N -C2014 11 18.23559 01 30 23.425-37 25 40.010.07 0.0722.12rVEM083W84
    CK14UR1N -C2014 11 18.23835 01 30 23.407-37 25 39.980.07 0.0722.15iVEM083W84
    CK14UR1N -C2014 11 27.22148 01 29 17.583-37 24 12.510.07 0.0722.71gVEM083W84
    CK14UR1N -C2014 12 11.11568 01 27 54.830-37 17 49.640.07 0.0721.94iVEM083W84
    CK14UR1N -C2015 01 09.10701 01 26 35.324-36 51 38.750.07 0.0722.80zVEM083W84
    CK14UR1N KC2015 08 11.61298001 47 05.427-37 26 12.910.13 0.1321.87GVEM083F51
    CK14UR1N -C2015 08 17.35747 01 46 47.505-37 37 39.810.07 0.0722.23rVEM083W84
    CK14UR1N -C2015 08 17.35883 01 46 47.517-37 37 39.890.07 0.0722.55gVEM083W84
    CK14UR1N -C2015 08 24.34452 01 46 18.605-37 51 28.610.07 0.0722.62gVEM083W84
    CK14UR1N -C2015 09 02.37787 01 45 30.196-38 08 52.300.07 0.0722.21YVEM083W84
    CK14UR1N -C2015 09 13.39051 01 44 15.863-38 28 51.620.07 0.0721.95iVEM083W84
    CK14UR1N -C2015 10 06.27435 01 40 59.774-39 03 19.840.07 0.0722.01zVEM083W84
    CK14UR1N -C2015 11 20.22851 01 33 55.078-39 29 32.570.07 0.0722.33zVEM083W84
    CK14UR1N -C2015 11 20.23556 01 33 55.010-39 29 32.480.07 0.0722.13iVEM083W84
    CK14UR1N -C2016 01 11.09386 01 29 57.738-38 50 26.060.07 0.0722.13rVEM083W84
    CK14UR1N -C2016 01 11.09524 01 29 57.729-38 50 25.960.07 0.0722.89gVEM083W84
    CK14UR1N  C2016 08 09.58536001 52 24.356-39 29 37.720.13 0.1322.16GVEM083F51
    CK14UR1N  C2016 08 09.59528201 52 24.325-39 29 39.110.13 0.1322.13GVEM083F51
    CK14UR1N -C2016 10 01.29899 01 46 40.180-41 11 31.780.07 0.0721.65rVEM083W84
    CK14UR1N -C2016 10 01.30036 01 46 40.173-41 11 32.000.07 0.0721.96gVEM083W84
    CK14UR1N -C2016 10 03.31546 01 46 20.177-41 14 24.530.07 0.0721.91rVEM083W84
    CK14UR1N -C2016 10 03.31682 01 46 20.167-41 14 24.590.07 0.0722.56gVEM083W84
    CK14UR1N KC2017 08 13.57144901 58 27.697-41 56 20.770.13 0.1321.81GVEM083F51
    CK14UR1N KC2017 08 14.58512301 58 24.711-41 58 44.070.13 0.1321.49GVEM083F51
    CK14UR1N KC2017 09 08.55424701 56 09.883-42 55 16.280.13 0.1321.76GVEM083F51
    CK14UR1N KC2017 09 30.42187801 52 49.635-43 36 32.720.13 0.1322.02GVEM083F51
    CK14UR1N -C2017 10 15.27208 01 50 05.746-43 57 07.300.07 0.0721.97gVEM083W84
    CK14UR1N -C2017 10 15.33777 01 50 04.988-43 57 11.800.07 0.0721.23zVEM083W84
    CK14UR1N -C2017 10 15.33915 01 50 04.970-43 57 11.890.07 0.0721.63rVEM083W84
    CK14UR1N KC2017 10 29.35825001 47 22.733-44 09 45.250.13 0.1321.54GVEM083F51
    CK14UR1N KC2017 11 06.33049701 45 51.862-44 13 42.340.13 0.1322.08GVEM083F51
    CK14UR1N KC2017 12 11.25003001 40 25.195-44 04 24.940.13 0.1321.53GVEM083F51
    CK14UR1N -C2017 12 15.18042 01 39 59.837-44 00 56.400.07 0.0722.04rVEM083W84
    CK14UR1N -C2017 12 15.18181 01 39 59.824-44 00 56.380.07 0.0722.44gVEM083W84
    CK14UR1N -C2018 10 21.24337 01 55 54.039-46 47 14.940.07 0.0721.60YVEM083W84
    CK14UR1N -C2018 10 27.17859 01 54 38.204-46 52 42.840.07 0.0721.43zVEM083W84
    CK14UR1N -C2018 11 08.23513 01 52 05.914-46 59 29.070.07 0.0721.63rVEM083W84
    CK14UR1N -C2018 11 08.23651 01 52 05.899-46 59 29.100.07 0.0721.57iVEM083W84
    CK14UR1N -C2018 11 08.23789 01 52 05.884-46 59 29.050.07 0.0722.22gVEM083W84
    CK14UR1N KC2019 08 19.59829602 14 55.242-47 31 52.430.13 0.1320.30GVEM083F51
    CK14UR1N  C2019 08 29.56986902 14 08.352-47 59 21.630.13 0.1320.58GVEM083F51
    CK14UR1N  C2019 08 29.58523402 14 08.234-47 59 24.180.13 0.1320.66GVEM083F51
    CK14UR1N  C2019 08 29.59292102 14 08.226-47 59 25.210.13 0.1320.52GVEM083F51
    CK14UR1N KC2021 06 22.13538 02 35 28.86 -51 07 43.1 0.10 0.10      VEM083L81
    CK14UR1N KC2021 06 22.16834 02 35 29.32 -51 07 47.8 0.10 0.1019.6 GVEM083L81
    CK14UR1N  C2021 06 22.16880502 35 29.32 -51 07 47.7 0.18 0.1819.8 GVEM083K93
    CK14UR1N  C2021 06 22.17258202 35 29.36 -51 07 48.5 0.18 0.1819.9 GVEM083K93
    CK14UR1N  C2021 06 22.17636102 35 29.38 -51 07 48.9 0.18 0.1819.9 GVEM083K93
    CK14UR1N  C2021 06 22.18014202 35 29.47 -51 07 49.2 0.18 0.1819.6 GVEM083K93
On Tuesday, June 29, 2021, 8:16:52 PM PDT, Marshall Eubanks <tme@...> wrote:


On 2021-06-29 11:32, Bill J. Gray wrote:
> Agreed on the unlikeliness of getting measurable non-gravs.
> (With caveats below.)
>
>    Carlos' list is extremely unlikely to prove specifically
> correct.  But it does suggest that we'll get a decent number of
> occultation opportunities over the coming years (just not of
> those specific stars).  We don't know _which_ stars yet or
> where the paths will be on the earth,  but we should get
> roughly the number of opportunities shown in his list.

If there is to be a mission to UN271, the best rendezvous time for a
flyby is  near the time of ecliptic passage, August 8, 2033, out at 11.9
AU at

Minimum energy orbits for a direct trajectories to UN271 exist, with one
launch window per year for the rest of this decade. These minimum energy
trajectories for launches up through 2029 _all_ flyby UN271
within 2 weeks of the time of its passage through the ecliptic plane. 
All of these opportunities from 2022-2029 have characteristic energies
(C_{3})  < 150 km^2/s^2, substantially less than the C_{3} of 170
km^2/s^2 required for the New Horizons probe to Pluto.

Based on a series of discussions with people who might actually launch
such a probe, I think that the 2026 window (which peaks on 2026-10-07)
is likely to be the earliest launch opportunity.

If such a mission goes forward, it would obviously be good if there were
occultation estimates of the orbit and object size and shape from  the
2024/2025 period. That (unfortunately for Northern Hemisphere observers)
will be at declinations of ~ -70 degrees.

Regards
Marshall


>
>    The first few will probably require the traditional IOTA
> method of saying "the uncertainty is several times the width
> of the ground track,  so let's get a heck of a lot of observers
> and/or put down temporary remote stations and figure that
> somebody will be in the right place."  As Brian says,  we
> might see some interesting photometric results as the star
> passes through the coma,  so even the near-miss stations might
> tell us something.
>
>    While we can't say much about specific occultations in 2028
> (start of Carlos' list),  we could make a multiple path width
> prediction for a "near-term" occultation,  much as was done
> for (486958) Arrokoth = 2014 MU69 = Ultima Thule before New
> Horizons visited it.  As with that object,  we'd quite likely
> have a failed effort or two before getting lucky.  (Though
> maybe not.  This object is about three times bigger than
> Arrokoth and half as far away.)
>
>    Depending on when it happened,  an occultation by a 100-km
> nucleus would last a minimum of about three seconds.  So
> it'd be long enough to get a decent size estimate.
>
>    The other value of occultations would be to really nail down
> the position of the object : "it was over the following star
> at exactly the following time,  and we know exactly where that
> star was because we have Gaia astrometry for it."  This has
> a couple of knock-on effects.  Give me a few such data points,
> and we'll have a much better orbit so that further occultation
> predictions will _not_ have multi-path-width uncertainties.
> And we might end up with a good enough orbit (very good
> astrometry over a couple of decades) so that very subtle
> effects,  such as non-gravs,  really _could_ be determined,
> even for such an enormous object.  In which case,  we might get
> a decent mass measurement after all.
>
>    For Arrokoth,  we started from Hubble astrometry... which,
> sadly,  may not happen this time.  But perhaps Gaia can get
> some data.
>
> -- Bill
>
> On 6/29/21 9:57 AM, Marshall Eubanks wrote:
>> On 2021-06-28 21:01, P. Clay Sherrod wrote:
>>> Personally it is my opinion that this far out, with so many unknown
>>> parameters still considered as variable factors for this unusual
>>> object, predicting occultations – unless in the immediate time frame
>>> – is unreliable and meaningless.  I believe that we are going to see
>>> some changes in orbital parameters of 2014 UN271 from both
>>> gravitational and non-gravitational forces in coming  months as the
>>> objects covers more space.  There is no reason for any of us to be
>>> planning occultation observations predicted for 2028 and 2029 at this
>>> time.
>>
>>
>> I fully agree. After July of 2024 the current UN271 ephemeris error
>> exceeds 1 Earth diameter, and there is clearly no reason to plan
>> anything at present for that period or after.
>>
>> The real question to me for now is, should money be raised to support
>> an occultation campaign in the Southern hemisphere in the next few
>> years?
>>
>> I would be very surprised if a 100 km body shows non-gravitational
>> forces visible with conventional optical astrometry. A 100 km body
>> will have 100 times the mass/area ratio of a 1 km body of the same
>> density.
>>
>> The highest mass determined from NG forcing in
>> https://academic.oup.com/mnras/article/393/1/192/1083616
>> is 4 x 10^14 kg or 1000 times smaller than the mass predicted for
>> UN271 with a 100 km diameter and a density of 0.4 gm/cm^3.
>>
>> However, if NG motions could be detected by occultation at the mas
>> level, I think that there _would_ be a decent chance of determining
>> the mass of UN271 from its NG forcing.
>>
>> Regards
>> Marshall
>>
>>>
>>> Dr. Clay
>>> Arkansas Sky Observatories
>>> www.arksky.org
>>> Petit Jean Mountain
>>> MPC H41 / MPC H43 / MPC H45
>>> .....serving astronomical sciences since 1971
>>>
>>> -----------------
>>>
>>> From: Sam Deen via groups.io
>>> Sent: Monday, June 28, 2021 7:53 PM
>>> To: mpml@groups.io ; Carlos Perelló
>>> Subject: Re: {MPML} 2014 UN271: cometary activity
>>>
>>> Hi Carlos,
>>>
>>> I'm not sure those are particularly accurate - at least, not enough
>>> for a particularly meaningful prediction. I think that this is more
>>> of
>>> a problem with occult than the orbit uncertainty, but for instance on
>>> 2028-10-05 14:40.8 find_orb records the comet as being at 10 59
>>> 13.715
>>> -61 58 11.58 which is several arcminutes from where this supposed
>>> occultation takes place. While I maintain that occultations are
>>> practically visible (and admittedly don't understand Larry's interest
>>> in discounting them unconditionally) I don't think they will be
>>> practical to predict with such an unusual orbit with Occult.
>>>
>>> ~Sam
>>>
>>> On Monday, June 28, 2021, 5:48:36 PM PDT, Carlos Perelló
>>> <rigilk436@...> wrote:
>>>
>>> I forgot to say the list is filtered by StarMag <12.6. Obviously at
>>> this time the predictions are very preliminary.
>>> Literally from the Help File of Occult: Note that the diameter is
>>> arbitrarily set at 10km, and the positional uncertainty is set at 3".
>>>
>>> Regards,
>>> Carlos
>>>
>>> El 24/06/2021 a las 13:11, Carlos Perelló escribió:
>>>
>>>>
>>>
>>> Using Occult, these are the occultations calculated until 2035:
>>>
>>>      Global summary of events - sorted by Date
>>>
>>>      Date       U.T.    Diameter   Durn  Star  Mag-Drop Elon  %
>>> Star         d Rely        Planet           Min        Moon     § ?
>>>  R.A. (J2000)  Dec.            Rec
>>>    y   m  d    h   m     km   "   sec/m   mag   V    R     o Ill
>>> No.            <1.4     No Name              D   Error Dist ill  ?
>>> h  m   s      o  '   "           #
>>> 2028 Dec  5   14 40.8    10 0.001  0.55s 12.3  8.2  8.6   69    
>>> UCAC4
>>> 140-057616 s 0.85      0 C/2014 UN271 (Be 1.28 ±4.08   89  86      10
>>> 58 27.269 -62  2 45.99         0
>>> 2028 Dec 17    9 15.7    10 0.001  0.62s 12.1  8.5  8.6   74    
>>> UCAC4
>>> 137-051856 s 4.05      0 C/2014 UN271 (Be 0.94 ±4.05   82   2      10
>>> 59 19.973 -62 36 36.98         1
>>> 2029 Jan  1    4 45.9    10 0.001  0.69s 12.6  7.9  8.1   81    
>>> UCAC4
>>> 134-047703 s 0.80      0 C/2014 UN271 (Be 5.14 ±4.00   96 100      10
>>> 58 10.418 -63 14  0.21         2
>>> 2029 Jan 31    4 18.6    10 0.001  0.59s 11.3  9.1  9.4   96     TYC
>>> 8965-01100-1 s 0.75      0 C/2014 UN271 (Be 4.47 ±3.90   75  99
>>> 10 48 24.876 -63 53 48.38         3
>>> 2029 Feb  3   17 51.4    10 0.001  0.56s 12.1  8.4  8.7   98    
>>> UCAC4
>>> 131-040285 s 0.80      0 C/2014 UN271 (Be 6.44 ±3.88   57  74      10
>>> 46 42.995 -63 54  2.93         4
>>>
>>> 2029 Dec 29   10 30.9    10 0.001  0.96s  9.7 10.5 10.3   80    
>>> UCAC4
>>> 193-062412 w 11.1      0 C/2014 UN271 (Be 3.60 ±3.84   43  38      11
>>> 42 34.634 -51 35 50.30         5
>>> 2029 Dec 29   11  7.6    10 0.001  0.94s 11.3  9.0  8.7   80    
>>> UCAC4
>>> 193-062409 w 0.95      0 C/2014 UN271 (Be 3.92 ±3.84   43  38      11
>>> 42 33.976 -51 35 52.60         6
>>> 2030 Jan  1   10  7.4    10 0.001   2.1s 10.7  9.5 10.4   82    
>>> UCAC4
>>> 192-059604 v 1.05      0 C/2014 UN271 (Be 6.15 ±3.83   58  10      11
>>> 42 27.748 -51 41 17.99         7
>>> 2032 Dec  5   20 30.3    10 0.001  0.63s 12.4  8.1  8.3   60    
>>> UCAC4
>>> 384-061530 s 1.05      0 C/2014 UN271 (Be 0.01 ±4.08   98  11      12
>>> 42 35.336 -13 13 18.53         8
>>> 2032 Dec 23    3 55.7    10 0.001  1.03s 12.0  8.4  8.7   77    
>>> UCAC4
>>> 385-061483 s 1.35      0 C/2014 UN271 (Be 0.41 ±3.99   32  66      12
>>> 45  2.980 -13  2 35.43         9
>>>
>>> 2033 Feb  2   22 47.8    10 0.001  0.56s 12.3  8.1  8.4  119    
>>> UCAC4
>>> 391-057575 s 4.20      0 C/2014 UN271 (Be 2.88 ±3.78  162  13      12
>>> 44 16.057 -11 51 12.27        10
>>> 2035 May 17   10 40.8    10 0.001  0.53s 11.0 10.3 10.6  126     TYC
>>> 1449-00435-1 s 1.00      0 C/2014 UN271 (Be 0.47 ±4.41   18  80
>>> 12 48 17.694  15 55 10.51        11
>>>
>>> Regards,
>>> Carlos
>>>
>>> El 24/06/2021 a las 12:41, andrew_j_walker via groups.io escribió:
>>>
>>>>
>>>
>>> Now we have a comet circular
>>> https://www.minorplanetcenter.net/mpec/K21/K21M83.html
>>>
>>> Nice work with the extra observations from F51 and 568, and in the
>>> last few days!
>>> Andrew
>>>
>>>
>>>
>>> Links:
>>> ------
>>> [1] https://groups.io/g/mpml/message/36525
>>> [2] https://groups.io/mt/83710102/2048683
>>> [3] https://groups.io/g/mpml/post
>>> [4] https://groups.io/g/mpml/editsub/2048683
>>> [5] https://groups.io/g/mpml/unsub
>>
>>
>>
>>
>>
>
>
>






Re: 2014 UN271: cometary activity

Marshall Eubanks
 

On 2021-06-29 11:32, Bill J. Gray wrote:
Agreed on the unlikeliness of getting measurable non-gravs.
(With caveats below.)
Carlos' list is extremely unlikely to prove specifically
correct. But it does suggest that we'll get a decent number of
occultation opportunities over the coming years (just not of
those specific stars). We don't know _which_ stars yet or
where the paths will be on the earth, but we should get
roughly the number of opportunities shown in his list.
If there is to be a mission to UN271, the best rendezvous time for a flyby is near the time of ecliptic passage, August 8, 2033, out at 11.9 AU at

Minimum energy orbits for a direct trajectories to UN271 exist, with one launch window per year for the rest of this decade. These minimum energy trajectories for launches up through 2029 _all_ flyby UN271
within 2 weeks of the time of its passage through the ecliptic plane. All of these opportunities from 2022-2029 have characteristic energies (C_{3}) < 150 km^2/s^2, substantially less than the C_{3} of 170 km^2/s^2 required for the New Horizons probe to Pluto.

Based on a series of discussions with people who might actually launch such a probe, I think that the 2026 window (which peaks on 2026-10-07) is likely to be the earliest launch opportunity.

If such a mission goes forward, it would obviously be good if there were occultation estimates of the orbit and object size and shape from the 2024/2025 period. That (unfortunately for Northern Hemisphere observers) will be at declinations of ~ -70 degrees.

Regards
Marshall


The first few will probably require the traditional IOTA
method of saying "the uncertainty is several times the width
of the ground track, so let's get a heck of a lot of observers
and/or put down temporary remote stations and figure that
somebody will be in the right place." As Brian says, we
might see some interesting photometric results as the star
passes through the coma, so even the near-miss stations might
tell us something.
While we can't say much about specific occultations in 2028
(start of Carlos' list), we could make a multiple path width
prediction for a "near-term" occultation, much as was done
for (486958) Arrokoth = 2014 MU69 = Ultima Thule before New
Horizons visited it. As with that object, we'd quite likely
have a failed effort or two before getting lucky. (Though
maybe not. This object is about three times bigger than
Arrokoth and half as far away.)
Depending on when it happened, an occultation by a 100-km
nucleus would last a minimum of about three seconds. So
it'd be long enough to get a decent size estimate.
The other value of occultations would be to really nail down
the position of the object : "it was over the following star
at exactly the following time, and we know exactly where that
star was because we have Gaia astrometry for it." This has
a couple of knock-on effects. Give me a few such data points,
and we'll have a much better orbit so that further occultation
predictions will _not_ have multi-path-width uncertainties.
And we might end up with a good enough orbit (very good
astrometry over a couple of decades) so that very subtle
effects, such as non-gravs, really _could_ be determined,
even for such an enormous object. In which case, we might get
a decent mass measurement after all.
For Arrokoth, we started from Hubble astrometry... which,
sadly, may not happen this time. But perhaps Gaia can get
some data.
-- Bill
On 6/29/21 9:57 AM, Marshall Eubanks wrote:
On 2021-06-28 21:01, P. Clay Sherrod wrote:
Personally it is my opinion that this far out, with so many unknown
parameters still considered as variable factors for this unusual
object, predicting occultations – unless in the immediate time frame
– is unreliable and meaningless.  I believe that we are going to see
some changes in orbital parameters of 2014 UN271 from both
gravitational and non-gravitational forces in coming  months as the
objects covers more space.  There is no reason for any of us to be
planning occultation observations predicted for 2028 and 2029 at this
time.
I fully agree. After July of 2024 the current UN271 ephemeris error exceeds 1 Earth diameter, and there is clearly no reason to plan anything at present for that period or after.
The real question to me for now is, should money be raised to support an occultation campaign in the Southern hemisphere in the next few years?
I would be very surprised if a 100 km body shows non-gravitational forces visible with conventional optical astrometry. A 100 km body will have 100 times the mass/area ratio of a 1 km body of the same density.
The highest mass determined from NG forcing in
https://academic.oup.com/mnras/article/393/1/192/1083616
is 4 x 10^14 kg or 1000 times smaller than the mass predicted for UN271 with a 100 km diameter and a density of 0.4 gm/cm^3.
However, if NG motions could be detected by occultation at the mas level, I think that there _would_ be a decent chance of determining the mass of UN271 from its NG forcing.
Regards
Marshall

Dr. Clay
Arkansas Sky Observatories
www.arksky.org
Petit Jean Mountain
MPC H41 / MPC H43 / MPC H45
.....serving astronomical sciences since 1971
-----------------
From: Sam Deen via groups.io
Sent: Monday, June 28, 2021 7:53 PM
To: mpml@groups.io ; Carlos Perelló
Subject: Re: {MPML} 2014 UN271: cometary activity
Hi Carlos,
I'm not sure those are particularly accurate - at least, not enough
for a particularly meaningful prediction. I think that this is more of
a problem with occult than the orbit uncertainty, but for instance on
2028-10-05 14:40.8 find_orb records the comet as being at 10 59 13.715
-61 58 11.58 which is several arcminutes from where this supposed
occultation takes place. While I maintain that occultations are
practically visible (and admittedly don't understand Larry's interest
in discounting them unconditionally) I don't think they will be
practical to predict with such an unusual orbit with Occult.
~Sam
On Monday, June 28, 2021, 5:48:36 PM PDT, Carlos Perelló
<rigilk436@...> wrote:
I forgot to say the list is filtered by StarMag <12.6. Obviously at
this time the predictions are very preliminary.
Literally from the Help File of Occult: Note that the diameter is
arbitrarily set at 10km, and the positional uncertainty is set at 3".
Regards,
Carlos
El 24/06/2021 a las 13:11, Carlos Perelló escribió:

Using Occult, these are the occultations calculated until 2035:
     Global summary of events - sorted by Date
     Date       U.T.    Diameter   Durn  Star  Mag-Drop Elon  %
Star         d Rely        Planet           Min        Moon     § ?
 R.A. (J2000)  Dec.            Rec
   y   m  d    h   m     km   "   sec/m   mag   V    R     o Ill
No.            <1.4     No Name              D   Error Dist ill  ?
h  m   s      o  '   "           #
2028 Dec  5   14 40.8    10 0.001  0.55s 12.3  8.2  8.6   69     UCAC4
140-057616 s 0.85      0 C/2014 UN271 (Be 1.28 ±4.08   89  86      10
58 27.269 -62  2 45.99         0
2028 Dec 17    9 15.7    10 0.001  0.62s 12.1  8.5  8.6   74     UCAC4
137-051856 s 4.05      0 C/2014 UN271 (Be 0.94 ±4.05   82   2      10
59 19.973 -62 36 36.98         1
2029 Jan  1    4 45.9    10 0.001  0.69s 12.6  7.9  8.1   81     UCAC4
134-047703 s 0.80      0 C/2014 UN271 (Be 5.14 ±4.00   96 100      10
58 10.418 -63 14  0.21         2
2029 Jan 31    4 18.6    10 0.001  0.59s 11.3  9.1  9.4   96     TYC
8965-01100-1 s 0.75      0 C/2014 UN271 (Be 4.47 ±3.90   75  99
10 48 24.876 -63 53 48.38         3
2029 Feb  3   17 51.4    10 0.001  0.56s 12.1  8.4  8.7   98     UCAC4
131-040285 s 0.80      0 C/2014 UN271 (Be 6.44 ±3.88   57  74      10
46 42.995 -63 54  2.93         4
2029 Dec 29   10 30.9    10 0.001  0.96s  9.7 10.5 10.3   80     UCAC4
193-062412 w 11.1      0 C/2014 UN271 (Be 3.60 ±3.84   43  38      11
42 34.634 -51 35 50.30         5
2029 Dec 29   11  7.6    10 0.001  0.94s 11.3  9.0  8.7   80     UCAC4
193-062409 w 0.95      0 C/2014 UN271 (Be 3.92 ±3.84   43  38      11
42 33.976 -51 35 52.60         6
2030 Jan  1   10  7.4    10 0.001   2.1s 10.7  9.5 10.4   82     UCAC4
192-059604 v 1.05      0 C/2014 UN271 (Be 6.15 ±3.83   58  10      11
42 27.748 -51 41 17.99         7
2032 Dec  5   20 30.3    10 0.001  0.63s 12.4  8.1  8.3   60     UCAC4
384-061530 s 1.05      0 C/2014 UN271 (Be 0.01 ±4.08   98  11      12
42 35.336 -13 13 18.53         8
2032 Dec 23    3 55.7    10 0.001  1.03s 12.0  8.4  8.7   77     UCAC4
385-061483 s 1.35      0 C/2014 UN271 (Be 0.41 ±3.99   32  66      12
45  2.980 -13  2 35.43         9
2033 Feb  2   22 47.8    10 0.001  0.56s 12.3  8.1  8.4  119     UCAC4
391-057575 s 4.20      0 C/2014 UN271 (Be 2.88 ±3.78  162  13      12
44 16.057 -11 51 12.27        10
2035 May 17   10 40.8    10 0.001  0.53s 11.0 10.3 10.6  126     TYC
1449-00435-1 s 1.00      0 C/2014 UN271 (Be 0.47 ±4.41   18  80
12 48 17.694  15 55 10.51        11
Regards,
Carlos
El 24/06/2021 a las 12:41, andrew_j_walker via groups.io escribió:

Now we have a comet circular
https://www.minorplanetcenter.net/mpec/K21/K21M83.html
Nice work with the extra observations from F51 and 568, and in the
last few days!
Andrew
Links:
------
[1] https://groups.io/g/mpml/message/36525
[2] https://groups.io/mt/83710102/2048683
[3] https://groups.io/g/mpml/post
[4] https://groups.io/g/mpml/editsub/2048683
[5] https://groups.io/g/mpml/unsub


Re: In Earth's penumbra

Jean-Claude Merlin
 

Yes, consequently it cannot be in the Earth’s penumbra which lies at the opposition.

 

 

De : mpml@groups.io [mailto:mpml@groups.io] De la part de tony873004
Envoyé : mardi 29 juin 2021 20:44
À : Jean-Claude Merlin
Cc : MPML
Objet : Re: {MPML} In Earth's penumbra

 

2013 YY40 is currently behind the Sun as viewed from Earth.

 

On Tue, Jun 29, 2021 at 10:29 AM Jean-Claude Merlin <jcmerlin@...> wrote:

Dear all,

 

Is there a bug in the following ephemeris from a MP at very small elongation from the Sun : “In Earth’s penumbra” ???

It would be preferably when elongation is near 180° ? No ?

 

Cheers

JC

 

2013 YY40

Display all designations for this object

Epoch 2020 Dec. 17.0 TT = JDT 2459200.5                 MPC
M 296.90208              (2000.0)            P               Q
n   0.26315950     Peri.   17.19870     -0.41812033     -0.90641986             T = 2459440.27065 JDT
a   2.4117004      Node    97.55097     +0.82617485     -0.40682795             q =     1.9971264
e   0.1719011      Incl.    3.45951     +0.37763807     -0.11355196    Earth MOID = 1.01378 AU
P   3.75           H   17.3           G   0.15           U   0
From 173 observations at 10 oppositions, 2003-2021, mean residual 0".38.

Last observed on 2021 Jan. 5. Perturbed ephemeris below based on elements from MPO 599489.

Further observations? Not necessary for numbering.

     K13Y40Y       [H=17.3]
Date       UT      R.A. (J2000) Decl.    Delta     r     El.    Ph.   V      Sky Motion
            h m s                                                            "/min    P.A.
2021 06 29 000000 06 32 16.6 +23 13 47   3.027   2.010    0.2   0.1  21.3    1.42    091.7 In Earth's penumbra
2021 06 30 000000 06 34 44.8 +23 12 42   3.026   2.010    0.2   0.1  21.3    1.42    091.9 In Earth's penumbra
2021 07 01 000000 06 37 13.1 +23 11 29   3.026   2.009    0.6   0.3  21.3    1.42    092.2

 


Re: [comets-ml] 2014 UN271: cometary activity

 

Hi All

Attached our follow-up image of this special comet C/2014 UN271 taken
on 2021 June 27 at 10UT from X02 (Telescope Live, Chile) with the
CHI-1 telescope that is a 0.61-m f/6.5 astrograph + CCD.

https://tinyurl.com/C2014UN271BB

Stacking of 13 unfiltered exposures, 240 seconds each, with an almost
full moon just 69 degree away, clearly shows the coma developed by
this object.
(Observers E. Guido, M. Rocchetto, E. Bryssinck, M. Fulle, G. Milani,
C. Nassef, G. Savini, A. Valvasori).

Direct links to the image:

https://tinyurl.com/C2014UN271

https://tinyurl.com/C2014UN271V2

Details of CHI-1 telescope:
https://help.telescope.live/hc/en-us/articles/360002557197-CHI-1-60cm-F6-5-Reflector

Kind Regards,

Ernesto Guido
http://remanzacco.blogspot.com
http://twitter.com/comets77

On Tue, Jun 22, 2021 at 12:25 PM Luca Buzzi <lucabuzzi.204@...> wrote:

Dear all,
we imaged it tonight with the 0.51-m SkyGems Remote Telescope in Namibia (45 x 90
seconds) and it has a clear cometary activity, with a 15" coma possibly elongated in
PA between 0 and 90°.
Its magnitude is 19.7 G with an aperture radius of 4.5", and 18.8 G with an aperture
of 7.5". Here you can see a cropped image:

https://www.astrogeo.va.it/astronomia/2014UN271_20210622_L81.png

Regards,
Luca Buzzi - MPC 204
Andrea Aletti - MPC 204
Lukas Demetz - MPC L81



Il 19/06/2021 08:48, Sam Deen via groups.io ha scritto:
Hi all,

Some very recent exciting news from the Dark Energy Survey collaboration (
https://minorplanetcenter.net/mpec/K21/K21M53.html
<https://minorplanetcenter.net/mpec/K21/K21M53.html> )

This new object, 2014 UN271, is not just unusual, but radically exceptional among all
known bodies in the Solar System to date. Discovered about 29 AU out from the Sun and
currently around 22 away, its orbit takes it from just beyond the orbit of Saturn
(10.9 AU) all the way out to the Oort Cloud - no, not the Hill Cloud. the Oort Cloud.
The incoming barycentric aphelion was 39,400 +/- 1200 AU, and outgoing it will be an
even huger 54,600 +/- 2300 AU (!!)

Peribarion 2031 Jan 21.574596 +/- 0.0666 TT = 13:47:25 (JD 2462888.074596)
Epoch 1000 Jan 1.0 TT = JDT 2086307.5 Find_Orb
M 359.86589747 +/- 0.006 (J2000 ecliptic)
n 0.00000035 +/- 1.73e-8 Peri. 326.27934 +/- 0.0006
a 19721.6906 +/- 665 Node 190.00285 +/- 0.000052
e 0.9994448 +/- 1.81e-5 Incl. 95.46628 +/- 0.000052
P2767738 H 7.8 G 0.15 U 0.7
q 10.9491955 +/- 0.000177 Q 39432.4321 +/- 1232
From 37 observations 2014 Aug. 28-2018 Nov. 8; mean residual 0".07

Peribarion 2031 Jan 21.542640 +/- 0.0662 TT = 13:01:24 (JD 2462888.042640)
Epoch 3000 Jan 1.0 TT = JDT 2816787.5 Find_Orb
M 0.07733589 +/- 0.0053 (J2000 ecliptic)
n 0.00000021 +/- 1.47e-8 Peri. 326.24537 +/- 0.0006
a 27310.4810 +/- 1288 Node 190.00938 +/- 0.000052
e 0.9995990 +/- 1.82e-5 Incl. 95.46057 +/- 0.000052
P4510273 H 7.8 G 0.15 U 0.6
q 10.9490073 +/- 0.000177 Q 54610.0131 +/- 2312
From 37 observations 2014 Aug. 28-2018 Nov. 8; mean residual 0".07

Based on the given absolute magnitude, and given how exceptionally red it looked in
2014 precovery images from CFHT (the g - r color was 0.9, and r - i was 0.5!) I would
estimate at an albedo of 0.01-0.08 a diameter of 130-370 kilometers (nominally 160)
which puts it on a similar scale, if not larger than, Sarabat's huge comet C/1729 P1,
and almost undoubtedly the largest Oort Cloud object ever discovered- almost in dwarf
planet territory!

I have little doubt in my mind that as this gets closer to the Sun, it will begin
displaying the coma and tail typical of every other object yet seen in its orbit. It
almost feels premature to ascribe any sort of theoretical slope to it with how little
precedent there is for objects like this, but if Hale-Bopp is any indication with its
slope of 20 at large distances, then 2014 UN271 could possibly reach magnitude 13 in
early 2031 - but I wouldn't count on much brighter than 16 or 17 just yet. Either
way, that's impressively bright, and this object should make an exceptional target of
study in the next couple of decades to accompany how exceptional an object it looks
to be.

~Sam




Re: In Earth's penumbra

tony873004
 

2013 YY40 is currently behind the Sun as viewed from Earth.


On Tue, Jun 29, 2021 at 10:29 AM Jean-Claude Merlin <jcmerlin@...> wrote:

Dear all,

 

Is there a bug in the following ephemeris from a MP at very small elongation from the Sun : “In Earth’s penumbra” ???

It would be preferably when elongation is near 180° ? No ?

 

Cheers

JC

 

2013 YY40

Display all designations for this object

Epoch 2020 Dec. 17.0 TT = JDT 2459200.5                 MPC
M 296.90208              (2000.0)            P               Q
n   0.26315950     Peri.   17.19870     -0.41812033     -0.90641986             T = 2459440.27065 JDT
a   2.4117004      Node    97.55097     +0.82617485     -0.40682795             q =     1.9971264
e   0.1719011      Incl.    3.45951     +0.37763807     -0.11355196    Earth MOID = 1.01378 AU
P   3.75           H   17.3           G   0.15           U   0
From 173 observations at 10 oppositions, 2003-2021, mean residual 0".38.

Last observed on 2021 Jan. 5. Perturbed ephemeris below based on elements from MPO 599489.

Further observations? Not necessary for numbering.

     K13Y40Y       [H=17.3]
Date       UT      R.A. (J2000) Decl.    Delta     r     El.    Ph.   V      Sky Motion
            h m s                                                            "/min    P.A.
2021 06 29 000000 06 32 16.6 +23 13 47   3.027   2.010    0.2   0.1  21.3    1.42    091.7 In Earth's penumbra
2021 06 30 000000 06 34 44.8 +23 12 42   3.026   2.010    0.2   0.1  21.3    1.42    091.9 In Earth's penumbra
2021 07 01 000000 06 37 13.1 +23 11 29   3.026   2.009    0.6   0.3  21.3    1.42    092.2

 


In Earth's penumbra

Jean-Claude Merlin
 

Dear all,

 

Is there a bug in the following ephemeris from a MP at very small elongation from the Sun : “In Earth’s penumbra” ???

It would be preferably when elongation is near 180° ? No ?

 

Cheers

JC

 

2013 YY40

Display all designations for this object

Epoch 2020 Dec. 17.0 TT = JDT 2459200.5                 MPC
M 296.90208              (2000.0)            P               Q
n   0.26315950     Peri.   17.19870     -0.41812033     -0.90641986             T = 2459440.27065 JDT
a   2.4117004      Node    97.55097     +0.82617485     -0.40682795             q =     1.9971264
e   0.1719011      Incl.    3.45951     +0.37763807     -0.11355196    Earth MOID = 1.01378 AU
P   3.75           H   17.3           G   0.15           U   0
From 173 observations at 10 oppositions, 2003-2021, mean residual 0".38.

Last observed on 2021 Jan. 5. Perturbed ephemeris below based on elements from MPO 599489.

Further observations? Not necessary for numbering.

     K13Y40Y       [H=17.3]
Date       UT      R.A. (J2000) Decl.    Delta     r     El.    Ph.   V      Sky Motion
            h m s                                                            "/min    P.A.
2021 06 29 000000 06 32 16.6 +23 13 47   3.027   2.010    0.2   0.1  21.3    1.42    091.7 In Earth's penumbra
2021 06 30 000000 06 34 44.8 +23 12 42   3.026   2.010    0.2   0.1  21.3    1.42    091.9 In Earth's penumbra
2021 07 01 000000 06 37 13.1 +23 11 29   3.026   2.009    0.6   0.3  21.3    1.42    092.2

 


Re: 2014 UN271: cometary activity

Bill J. Gray
 

Agreed on the unlikeliness of getting measurable non-gravs.
(With caveats below.)

Carlos' list is extremely unlikely to prove specifically
correct. But it does suggest that we'll get a decent number of
occultation opportunities over the coming years (just not of
those specific stars). We don't know _which_ stars yet or
where the paths will be on the earth, but we should get
roughly the number of opportunities shown in his list.

The first few will probably require the traditional IOTA
method of saying "the uncertainty is several times the width
of the ground track, so let's get a heck of a lot of observers
and/or put down temporary remote stations and figure that
somebody will be in the right place." As Brian says, we
might see some interesting photometric results as the star
passes through the coma, so even the near-miss stations might
tell us something.

While we can't say much about specific occultations in 2028
(start of Carlos' list), we could make a multiple path width
prediction for a "near-term" occultation, much as was done
for (486958) Arrokoth = 2014 MU69 = Ultima Thule before New
Horizons visited it. As with that object, we'd quite likely
have a failed effort or two before getting lucky. (Though
maybe not. This object is about three times bigger than
Arrokoth and half as far away.)

Depending on when it happened, an occultation by a 100-km
nucleus would last a minimum of about three seconds. So
it'd be long enough to get a decent size estimate.

The other value of occultations would be to really nail down
the position of the object : "it was over the following star
at exactly the following time, and we know exactly where that
star was because we have Gaia astrometry for it." This has
a couple of knock-on effects. Give me a few such data points,
and we'll have a much better orbit so that further occultation
predictions will _not_ have multi-path-width uncertainties.
And we might end up with a good enough orbit (very good
astrometry over a couple of decades) so that very subtle
effects, such as non-gravs, really _could_ be determined,
even for such an enormous object. In which case, we might get
a decent mass measurement after all.

For Arrokoth, we started from Hubble astrometry... which,
sadly, may not happen this time. But perhaps Gaia can get
some data.

-- Bill

On 6/29/21 9:57 AM, Marshall Eubanks wrote:
On 2021-06-28 21:01, P. Clay Sherrod wrote:
Personally it is my opinion that this far out, with so many unknown
parameters still considered as variable factors for this unusual
object, predicting occultations – unless in the immediate time frame
– is unreliable and meaningless.  I believe that we are going to see
some changes in orbital parameters of 2014 UN271 from both
gravitational and non-gravitational forces in coming  months as the
objects covers more space.  There is no reason for any of us to be
planning occultation observations predicted for 2028 and 2029 at this
time.
I fully agree. After July of 2024 the current UN271 ephemeris error exceeds 1 Earth diameter, and there is clearly no reason to plan anything at present for that period or after.
The real question to me for now is, should money be raised to support an occultation campaign in the Southern hemisphere in the next few years?
I would be very surprised if a 100 km body shows non-gravitational forces visible with conventional optical astrometry. A 100 km body will have 100 times the mass/area ratio of a 1 km body of the same density.
The highest mass determined from NG forcing in
https://academic.oup.com/mnras/article/393/1/192/1083616
is 4 x 10^14 kg or 1000 times smaller than the mass predicted for UN271 with a 100 km diameter and a density of 0.4 gm/cm^3.
However, if NG motions could be detected by occultation at the mas level, I think that there _would_ be a decent chance of determining the mass of UN271 from its NG forcing.
Regards
Marshall


Dr. Clay
Arkansas Sky Observatories
www.arksky.org
Petit Jean Mountain
MPC H41 / MPC H43 / MPC H45
.....serving astronomical sciences since 1971

-----------------

From: Sam Deen via groups.io
Sent: Monday, June 28, 2021 7:53 PM
To: mpml@groups.io ; Carlos Perelló
Subject: Re: {MPML} 2014 UN271: cometary activity

Hi Carlos,

I'm not sure those are particularly accurate - at least, not enough
for a particularly meaningful prediction. I think that this is more of
a problem with occult than the orbit uncertainty, but for instance on
2028-10-05 14:40.8 find_orb records the comet as being at 10 59 13.715
-61 58 11.58 which is several arcminutes from where this supposed
occultation takes place. While I maintain that occultations are
practically visible (and admittedly don't understand Larry's interest
in discounting them unconditionally) I don't think they will be
practical to predict with such an unusual orbit with Occult.

~Sam

On Monday, June 28, 2021, 5:48:36 PM PDT, Carlos Perelló
<rigilk436@...> wrote:

I forgot to say the list is filtered by StarMag <12.6. Obviously at
this time the predictions are very preliminary.
Literally from the Help File of Occult: Note that the diameter is
arbitrarily set at 10km, and the positional uncertainty is set at 3".

Regards,
Carlos

El 24/06/2021 a las 13:11, Carlos Perelló escribió:

Using Occult, these are the occultations calculated until 2035:

     Global summary of events - sorted by Date

     Date       U.T.    Diameter   Durn  Star  Mag-Drop Elon  %
Star         d Rely        Planet           Min        Moon     § ?
 R.A. (J2000)  Dec.            Rec
   y   m  d    h   m     km   "   sec/m   mag   V    R     o Ill
No.            <1.4     No Name              D   Error Dist ill  ?
h  m   s      o  '   "           #
2028 Dec  5   14 40.8    10 0.001  0.55s 12.3  8.2  8.6   69     UCAC4
140-057616 s 0.85      0 C/2014 UN271 (Be 1.28 ±4.08   89  86      10
58 27.269 -62  2 45.99         0
2028 Dec 17    9 15.7    10 0.001  0.62s 12.1  8.5  8.6   74     UCAC4
137-051856 s 4.05      0 C/2014 UN271 (Be 0.94 ±4.05   82   2      10
59 19.973 -62 36 36.98         1
2029 Jan  1    4 45.9    10 0.001  0.69s 12.6  7.9  8.1   81     UCAC4
134-047703 s 0.80      0 C/2014 UN271 (Be 5.14 ±4.00   96 100      10
58 10.418 -63 14  0.21         2
2029 Jan 31    4 18.6    10 0.001  0.59s 11.3  9.1  9.4   96     TYC
8965-01100-1 s 0.75      0 C/2014 UN271 (Be 4.47 ±3.90   75  99
10 48 24.876 -63 53 48.38         3
2029 Feb  3   17 51.4    10 0.001  0.56s 12.1  8.4  8.7   98     UCAC4
131-040285 s 0.80      0 C/2014 UN271 (Be 6.44 ±3.88   57  74      10
46 42.995 -63 54  2.93         4

2029 Dec 29   10 30.9    10 0.001  0.96s  9.7 10.5 10.3   80     UCAC4
193-062412 w 11.1      0 C/2014 UN271 (Be 3.60 ±3.84   43  38      11
42 34.634 -51 35 50.30         5
2029 Dec 29   11  7.6    10 0.001  0.94s 11.3  9.0  8.7   80     UCAC4
193-062409 w 0.95      0 C/2014 UN271 (Be 3.92 ±3.84   43  38      11
42 33.976 -51 35 52.60         6
2030 Jan  1   10  7.4    10 0.001   2.1s 10.7  9.5 10.4   82     UCAC4
192-059604 v 1.05      0 C/2014 UN271 (Be 6.15 ±3.83   58  10      11
42 27.748 -51 41 17.99         7
2032 Dec  5   20 30.3    10 0.001  0.63s 12.4  8.1  8.3   60     UCAC4
384-061530 s 1.05      0 C/2014 UN271 (Be 0.01 ±4.08   98  11      12
42 35.336 -13 13 18.53         8
2032 Dec 23    3 55.7    10 0.001  1.03s 12.0  8.4  8.7   77     UCAC4
385-061483 s 1.35      0 C/2014 UN271 (Be 0.41 ±3.99   32  66      12
45  2.980 -13  2 35.43         9

2033 Feb  2   22 47.8    10 0.001  0.56s 12.3  8.1  8.4  119     UCAC4
391-057575 s 4.20      0 C/2014 UN271 (Be 2.88 ±3.78  162  13      12
44 16.057 -11 51 12.27        10
2035 May 17   10 40.8    10 0.001  0.53s 11.0 10.3 10.6  126     TYC
1449-00435-1 s 1.00      0 C/2014 UN271 (Be 0.47 ±4.41   18  80
12 48 17.694  15 55 10.51        11

Regards,
Carlos

El 24/06/2021 a las 12:41, andrew_j_walker via groups.io escribió:

Now we have a comet circular
https://www.minorplanetcenter.net/mpec/K21/K21M83.html

Nice work with the extra observations from F51 and 568, and in the
last few days!
Andrew



Links:
------
[1] https://groups.io/g/mpml/message/36525
[2] https://groups.io/mt/83710102/2048683
[3] https://groups.io/g/mpml/post
[4] https://groups.io/g/mpml/editsub/2048683
[5] https://groups.io/g/mpml/unsub


Re: 2014 UN271: cometary activity

Marshall Eubanks
 

On 2021-06-28 21:01, P. Clay Sherrod wrote:
Personally it is my opinion that this far out, with so many unknown
parameters still considered as variable factors for this unusual
object, predicting occultations – unless in the immediate time frame
– is unreliable and meaningless. I believe that we are going to see
some changes in orbital parameters of 2014 UN271 from both
gravitational and non-gravitational forces in coming months as the
objects covers more space. There is no reason for any of us to be
planning occultation observations predicted for 2028 and 2029 at this
time.

I fully agree. After July of 2024 the current UN271 ephemeris error exceeds 1 Earth diameter, and there is clearly no reason to plan anything at present for that period or after.

The real question to me for now is, should money be raised to support an occultation campaign in the Southern hemisphere in the next few years?

I would be very surprised if a 100 km body shows non-gravitational forces visible with conventional optical astrometry. A 100 km body will have 100 times the mass/area ratio of a 1 km body of the same density.

The highest mass determined from NG forcing in
https://academic.oup.com/mnras/article/393/1/192/1083616
is 4 x 10^14 kg or 1000 times smaller than the mass predicted for UN271 with a 100 km diameter and a density of 0.4 gm/cm^3.

However, if NG motions could be detected by occultation at the mas level, I think that there _would_ be a decent chance of determining the mass of UN271 from its NG forcing.

Regards
Marshall

Dr. Clay
Arkansas Sky Observatories
www.arksky.org
Petit Jean Mountain
MPC H41 / MPC H43 / MPC H45
.....serving astronomical sciences since 1971
-----------------
From: Sam Deen via groups.io
Sent: Monday, June 28, 2021 7:53 PM
To: mpml@groups.io ; Carlos Perelló
Subject: Re: {MPML} 2014 UN271: cometary activity
Hi Carlos,
I'm not sure those are particularly accurate - at least, not enough
for a particularly meaningful prediction. I think that this is more of
a problem with occult than the orbit uncertainty, but for instance on
2028-10-05 14:40.8 find_orb records the comet as being at 10 59 13.715
-61 58 11.58 which is several arcminutes from where this supposed
occultation takes place. While I maintain that occultations are
practically visible (and admittedly don't understand Larry's interest
in discounting them unconditionally) I don't think they will be
practical to predict with such an unusual orbit with Occult.
~Sam
On Monday, June 28, 2021, 5:48:36 PM PDT, Carlos Perelló
<rigilk436@...> wrote:
I forgot to say the list is filtered by StarMag <12.6. Obviously at
this time the predictions are very preliminary.
Literally from the Help File of Occult: Note that the diameter is
arbitrarily set at 10km, and the positional uncertainty is set at 3".
Regards,
Carlos
El 24/06/2021 a las 13:11, Carlos Perelló escribió:

Using Occult, these are the occultations calculated until 2035:
Global summary of events - sorted by Date
Date U.T. Diameter Durn Star Mag-Drop Elon %
Star d Rely Planet Min Moon § ?
R.A. (J2000) Dec. Rec
y m d h m km " sec/m mag V R o Ill
No. <1.4 No Name D Error Dist ill ?
h m s o ' " #
2028 Dec 5 14 40.8 10 0.001 0.55s 12.3 8.2 8.6 69 UCAC4
140-057616 s 0.85 0 C/2014 UN271 (Be 1.28 ±4.08 89 86 10
58 27.269 -62 2 45.99 0
2028 Dec 17 9 15.7 10 0.001 0.62s 12.1 8.5 8.6 74 UCAC4
137-051856 s 4.05 0 C/2014 UN271 (Be 0.94 ±4.05 82 2 10
59 19.973 -62 36 36.98 1
2029 Jan 1 4 45.9 10 0.001 0.69s 12.6 7.9 8.1 81 UCAC4
134-047703 s 0.80 0 C/2014 UN271 (Be 5.14 ±4.00 96 100 10
58 10.418 -63 14 0.21 2
2029 Jan 31 4 18.6 10 0.001 0.59s 11.3 9.1 9.4 96 TYC
8965-01100-1 s 0.75 0 C/2014 UN271 (Be 4.47 ±3.90 75 99
10 48 24.876 -63 53 48.38 3
2029 Feb 3 17 51.4 10 0.001 0.56s 12.1 8.4 8.7 98 UCAC4
131-040285 s 0.80 0 C/2014 UN271 (Be 6.44 ±3.88 57 74 10
46 42.995 -63 54 2.93 4
2029 Dec 29 10 30.9 10 0.001 0.96s 9.7 10.5 10.3 80 UCAC4
193-062412 w 11.1 0 C/2014 UN271 (Be 3.60 ±3.84 43 38 11
42 34.634 -51 35 50.30 5
2029 Dec 29 11 7.6 10 0.001 0.94s 11.3 9.0 8.7 80 UCAC4
193-062409 w 0.95 0 C/2014 UN271 (Be 3.92 ±3.84 43 38 11
42 33.976 -51 35 52.60 6
2030 Jan 1 10 7.4 10 0.001 2.1s 10.7 9.5 10.4 82 UCAC4
192-059604 v 1.05 0 C/2014 UN271 (Be 6.15 ±3.83 58 10 11
42 27.748 -51 41 17.99 7
2032 Dec 5 20 30.3 10 0.001 0.63s 12.4 8.1 8.3 60 UCAC4
384-061530 s 1.05 0 C/2014 UN271 (Be 0.01 ±4.08 98 11 12
42 35.336 -13 13 18.53 8
2032 Dec 23 3 55.7 10 0.001 1.03s 12.0 8.4 8.7 77 UCAC4
385-061483 s 1.35 0 C/2014 UN271 (Be 0.41 ±3.99 32 66 12
45 2.980 -13 2 35.43 9
2033 Feb 2 22 47.8 10 0.001 0.56s 12.3 8.1 8.4 119 UCAC4
391-057575 s 4.20 0 C/2014 UN271 (Be 2.88 ±3.78 162 13 12
44 16.057 -11 51 12.27 10
2035 May 17 10 40.8 10 0.001 0.53s 11.0 10.3 10.6 126 TYC
1449-00435-1 s 1.00 0 C/2014 UN271 (Be 0.47 ±4.41 18 80
12 48 17.694 15 55 10.51 11
Regards,
Carlos
El 24/06/2021 a las 12:41, andrew_j_walker via groups.io escribió:

Now we have a comet circular
https://www.minorplanetcenter.net/mpec/K21/K21M83.html
Nice work with the extra observations from F51 and 568, and in the
last few days!
Andrew
Links:
------
[1] https://groups.io/g/mpml/message/36525
[2] https://groups.io/mt/83710102/2048683
[3] https://groups.io/g/mpml/post
[4] https://groups.io/g/mpml/editsub/2048683
[5] https://groups.io/g/mpml/unsub


Re: 2014 UN271: cometary activity

Carlos Perelló
 

I fully agree. That list was for curiosity. We don't have good figures yet. We still have some years forward...

Carlos

El 29/06/2021 a las 3:01, P. Clay Sherrod escribió:

Personally it is my opinion that this far out, with so many unknown parameters still considered as variable factors for this unusual object, predicting occultations – unless in the immediate time frame – is unreliable and meaningless.  I believe that we are going to see some changes in orbital parameters of 2014 UN271 from both gravitational and non-gravitational forces in coming  months as the objects covers more space.  There is no reason for any of us to be planning occultation observations predicted for 2028 and 2029 at this time.
 
Dr. Clay
Arkansas Sky Observatories
www.arksky.org
Petit Jean Mountain
MPC H41 / MPC H43 / MPC H45
.....serving astronomical sciences since 1971

-----------------
 
Sent: Monday, June 28, 2021 7:53 PM
Subject: Re: {MPML} 2014 UN271: cometary activity
 
Hi Carlos,
 
I'm not sure those are particularly accurate - at least, not enough for a particularly meaningful prediction. I think that this is more of a problem with occult than the orbit uncertainty, but for instance on 2028-10-05 14:40.8 find_orb records the comet as being at 10 59 13.715 -61 58 11.58 which is several arcminutes from where this supposed occultation takes place. While I maintain that occultations are practically visible (and admittedly don't understand Larry's interest in discounting them unconditionally) I don't think they will be practical to predict with such an unusual orbit with Occult.
 
~Sam
 
On Monday, June 28, 2021, 5:48:36 PM PDT, Carlos Perelló <rigilk436@...> wrote:
 
 
I forgot to say the list is filtered by StarMag <12.6. Obviously at this time the predictions are very preliminary.
Literally from the Help File of Occult: Note that the diameter is arbitrarily set at 10km, and the positional uncertainty is set at 3".

Regards,
Carlos

El 24/06/2021 a las 13:11, Carlos Perelló escribió:
Using Occult, these are the occultations calculated until 2035:

     Global summary of events - sorted by Date

     Date       U.T.    Diameter   Durn  Star  Mag-Drop Elon  %      Star         d Rely        Planet           Min        Moon     § ?    R.A. (J2000)  Dec.            Rec
   y   m  d    h   m     km   "   sec/m   mag   V    R     o Ill     No.            <1.4     No Name              D   Error Dist ill  ?    h  m   s      o  '   "           #
2028 Dec  5   14 40.8    10 0.001  0.55s 12.3  8.2  8.6   69     UCAC4 140-057616 s 0.85      0 C/2014 UN271 (Be 1.28 ±4.08   89  86      10 58 27.269 -62  2 45.99         0
2028 Dec 17    9 15.7    10 0.001  0.62s 12.1  8.5  8.6   74     UCAC4 137-051856 s 4.05      0 C/2014 UN271 (Be 0.94 ±4.05   82   2      10 59 19.973 -62 36 36.98         1
2029 Jan  1    4 45.9    10 0.001  0.69s 12.6  7.9  8.1   81     UCAC4 134-047703 s 0.80      0 C/2014 UN271 (Be 5.14 ±4.00   96 100      10 58 10.418 -63 14  0.21         2
2029 Jan 31    4 18.6    10 0.001  0.59s 11.3  9.1  9.4   96     TYC 8965-01100-1 s 0.75      0 C/2014 UN271 (Be 4.47 ±3.90   75  99      10 48 24.876 -63 53 48.38         3
2029 Feb  3   17 51.4    10 0.001  0.56s 12.1  8.4  8.7   98     UCAC4 131-040285 s 0.80      0 C/2014 UN271 (Be 6.44 ±3.88   57  74      10 46 42.995 -63 54  2.93         4

2029 Dec 29   10 30.9    10 0.001  0.96s  9.7 10.5 10.3   80     UCAC4 193-062412 w 11.1      0 C/2014 UN271 (Be 3.60 ±3.84   43  38      11 42 34.634 -51 35 50.30         5
2029 Dec 29   11  7.6    10 0.001  0.94s 11.3  9.0  8.7   80     UCAC4 193-062409 w 0.95      0 C/2014 UN271 (Be 3.92 ±3.84   43  38      11 42 33.976 -51 35 52.60         6
2030 Jan  1   10  7.4    10 0.001   2.1s 10.7  9.5 10.4   82     UCAC4 192-059604 v 1.05      0 C/2014 UN271 (Be 6.15 ±3.83   58  10      11 42 27.748 -51 41 17.99         7
2032 Dec  5   20 30.3    10 0.001  0.63s 12.4  8.1  8.3   60     UCAC4 384-061530 s 1.05      0 C/2014 UN271 (Be 0.01 ±4.08   98  11      12 42 35.336 -13 13 18.53         8
2032 Dec 23    3 55.7    10 0.001  1.03s 12.0  8.4  8.7   77     UCAC4 385-061483 s 1.35      0 C/2014 UN271 (Be 0.41 ±3.99   32  66      12 45  2.980 -13  2 35.43         9

2033 Feb  2   22 47.8    10 0.001  0.56s 12.3  8.1  8.4  119     UCAC4 391-057575 s 4.20      0 C/2014 UN271 (Be 2.88 ±3.78  162  13      12 44 16.057 -11 51 12.27        10
2035 May 17   10 40.8    10 0.001  0.53s 11.0 10.3 10.6  126     TYC 1449-00435-1 s 1.00      0 C/2014 UN271 (Be 0.47 ±4.41   18  80      12 48 17.694  15 55 10.51        11

Regards,
Carlos


El 24/06/2021 a las 12:41, andrew_j_walker via groups.io escribió:
Now we have a comet circular https://www.minorplanetcenter.net/mpec/K21/K21M83.html

Nice work with the extra observations from F51 and 568, and in the last few days!
Andrew



Re: NEOWISE asteroid N0020xg recovered at magnitude 22.7 - how dark does that make it?

Adrien Coffinet
 

Close approaches of Earth.

Adrien


Le mar. 29 juin 2021 02:07, <tme@...> a écrit :
On 2021-06-28 17:49, Adrien Coffinet wrote:
> Hi all,
>
> Too few observations so far to be sure, but it looks like it could be
> a quasi-satellite of Mars. It came 0.14 au away from the Earth in

Are these close approaches of Mars or of Earth?

Regards
Marshall

> March 2014, soon after its discovery. The nominal orbit in JPL's SBDB
> gives a close approach at 0.06 au in 2031, but the uncertainty is
> large...
>
> Adrien
>
> Le lun. 28 juin 2021 21:20, Sam Deen via groups.io [1]
> <planetaryscience=yahoo.com@groups.io> a écrit :
>
>> Hi Dave,
>>
>> Thanks for your comments. The asteroid has been published as 2014
>> CS34 ( https://minorplanetcenter.net/mpec/K21/K21MA2.html )
>>
>> Upon some further research it seemed that part of the huge
>> difference was that it has a very high-amplitude light curve: over
>> the 20 minutes of observations it cycled around three or four times
>> between magnitude ~22.1 and ~22.9. Furthermore, some earlier
>> PANSTARRS observations put it as a few tenths of a magnitude
>> brighter, so it looks like the actual disparity is more around 4.0
>> mag than 4.6 mag- but still sounds like a bit more than your usual
>> difference!
>>
>> ~Sam
>>
>> On Sunday, June 27, 2021, 6:49:00 PM PDT, David Tholen
>> <tholen@...> wrote:
>>
>>> a factor of over 70 times dimmer than expected by WISE.
>>
>> I've seen differences as large as 3 mag before; 4.6 mag is
>> probably a record.  When doing follow-up of NEOWISE NEOCP
>> objects, we automatically assume at least 1.5 mag fainter
>> when choosing an exposure time, until a visible-light
>> observation is secured to clarify its visible magnitude.
> >
> Links:
> ------
> [1] http://groups.io
> [2] https://groups.io/g/mpml/message/36520
> [3] https://groups.io/mt/83832995/2048683
> [4] https://groups.io/g/mpml/post
> [5] https://groups.io/g/mpml/editsub/2048683
> [6] https://groups.io/g/mpml/unsub


Re: 2014 UN271: cometary activity

Brian Skiff
 

Athough I agree that predicting legit occultations for this object is premature, unless they happen soon, I wonder about other sorts of observations that might be useful during close appulses. I argued with Larry about this, but perhaps I can ask here as questions.
Would there be any value in examining the density profile of the coma from close appulses observed photometrically? Perhaps one wouldn’t expect anything other than the usual 1-over-rho profiles.
The other idea was that perhaps one could use spectroscopy of the occulted star to get the comet abundances differentially as the appulse occurs. Is that unworkable?
Just trying to think outside the diameters/shape-and-that’s-all box. Seems like there’s other stuff you could determine from such events that would not require an actual occultation.


\Brian


Re: 2014 UN271: cometary activity

P. Clay Sherrod
 

Personally it is my opinion that this far out, with so many unknown parameters still considered as variable factors for this unusual object, predicting occultations – unless in the immediate time frame – is unreliable and meaningless.  I believe that we are going to see some changes in orbital parameters of 2014 UN271 from both gravitational and non-gravitational forces in coming  months as the objects covers more space.  There is no reason for any of us to be planning occultation observations predicted for 2028 and 2029 at this time.
 
Dr. Clay
Arkansas Sky Observatories
www.arksky.org
Petit Jean Mountain
MPC H41 / MPC H43 / MPC H45
.....serving astronomical sciences since 1971

-----------------
 
Sent: Monday, June 28, 2021 7:53 PM
Subject: Re: {MPML} 2014 UN271: cometary activity
 
Hi Carlos,
 
I'm not sure those are particularly accurate - at least, not enough for a particularly meaningful prediction. I think that this is more of a problem with occult than the orbit uncertainty, but for instance on 2028-10-05 14:40.8 find_orb records the comet as being at 10 59 13.715 -61 58 11.58 which is several arcminutes from where this supposed occultation takes place. While I maintain that occultations are practically visible (and admittedly don't understand Larry's interest in discounting them unconditionally) I don't think they will be practical to predict with such an unusual orbit with Occult.
 
~Sam
 
On Monday, June 28, 2021, 5:48:36 PM PDT, Carlos Perelló <rigilk436@...> wrote:
 
 
I forgot to say the list is filtered by StarMag <12.6. Obviously at this time the predictions are very preliminary.
Literally from the Help File of Occult: Note that the diameter is arbitrarily set at 10km, and the positional uncertainty is set at 3".

Regards,
Carlos

El 24/06/2021 a las 13:11, Carlos Perelló escribió:
Using Occult, these are the occultations calculated until 2035:

     Global summary of events - sorted by Date

     Date       U.T.    Diameter   Durn  Star  Mag-Drop Elon  %      Star         d Rely        Planet           Min        Moon     § ?    R.A. (J2000)  Dec.            Rec
   y   m  d    h   m     km   "   sec/m   mag   V    R     o Ill     No.            <1.4     No Name              D   Error Dist ill  ?    h  m   s      o  '   "           #
2028 Dec  5   14 40.8    10 0.001  0.55s 12.3  8.2  8.6   69     UCAC4 140-057616 s 0.85      0 C/2014 UN271 (Be 1.28 ±4.08   89  86      10 58 27.269 -62  2 45.99         0
2028 Dec 17    9 15.7    10 0.001  0.62s 12.1  8.5  8.6   74     UCAC4 137-051856 s 4.05      0 C/2014 UN271 (Be 0.94 ±4.05   82   2      10 59 19.973 -62 36 36.98         1
2029 Jan  1    4 45.9    10 0.001  0.69s 12.6  7.9  8.1   81     UCAC4 134-047703 s 0.80      0 C/2014 UN271 (Be 5.14 ±4.00   96 100      10 58 10.418 -63 14  0.21         2
2029 Jan 31    4 18.6    10 0.001  0.59s 11.3  9.1  9.4   96     TYC 8965-01100-1 s 0.75      0 C/2014 UN271 (Be 4.47 ±3.90   75  99      10 48 24.876 -63 53 48.38         3
2029 Feb  3   17 51.4    10 0.001  0.56s 12.1  8.4  8.7   98     UCAC4 131-040285 s 0.80      0 C/2014 UN271 (Be 6.44 ±3.88   57  74      10 46 42.995 -63 54  2.93         4

2029 Dec 29   10 30.9    10 0.001  0.96s  9.7 10.5 10.3   80     UCAC4 193-062412 w 11.1      0 C/2014 UN271 (Be 3.60 ±3.84   43  38      11 42 34.634 -51 35 50.30         5
2029 Dec 29   11  7.6    10 0.001  0.94s 11.3  9.0  8.7   80     UCAC4 193-062409 w 0.95      0 C/2014 UN271 (Be 3.92 ±3.84   43  38      11 42 33.976 -51 35 52.60         6
2030 Jan  1   10  7.4    10 0.001   2.1s 10.7  9.5 10.4   82     UCAC4 192-059604 v 1.05      0 C/2014 UN271 (Be 6.15 ±3.83   58  10      11 42 27.748 -51 41 17.99         7
2032 Dec  5   20 30.3    10 0.001  0.63s 12.4  8.1  8.3   60     UCAC4 384-061530 s 1.05      0 C/2014 UN271 (Be 0.01 ±4.08   98  11      12 42 35.336 -13 13 18.53         8
2032 Dec 23    3 55.7    10 0.001  1.03s 12.0  8.4  8.7   77     UCAC4 385-061483 s 1.35      0 C/2014 UN271 (Be 0.41 ±3.99   32  66      12 45  2.980 -13  2 35.43         9

2033 Feb  2   22 47.8    10 0.001  0.56s 12.3  8.1  8.4  119     UCAC4 391-057575 s 4.20      0 C/2014 UN271 (Be 2.88 ±3.78  162  13      12 44 16.057 -11 51 12.27        10
2035 May 17   10 40.8    10 0.001  0.53s 11.0 10.3 10.6  126     TYC 1449-00435-1 s 1.00      0 C/2014 UN271 (Be 0.47 ±4.41   18  80      12 48 17.694  15 55 10.51        11

Regards,
Carlos


El 24/06/2021 a las 12:41, andrew_j_walker via groups.io escribió:
Now we have a comet circular https://www.minorplanetcenter.net/mpec/K21/K21M83.html

Nice work with the extra observations from F51 and 568, and in the last few days!
Andrew


Re: 2014 UN271: cometary activity

Sam Deen
 

Hi Carlos,

I'm not sure those are particularly accurate - at least, not enough for a particularly meaningful prediction. I think that this is more of a problem with occult than the orbit uncertainty, but for instance on 2028-10-05 14:40.8 find_orb records the comet as being at 10 59 13.715 -61 58 11.58 which is several arcminutes from where this supposed occultation takes place. While I maintain that occultations are practically visible (and admittedly don't understand Larry's interest in discounting them unconditionally) I don't think they will be practical to predict with such an unusual orbit with Occult.

~Sam

On Monday, June 28, 2021, 5:48:36 PM PDT, Carlos Perelló <rigilk436@...> wrote:


I forgot to say the list is filtered by StarMag <12.6. Obviously at this time the predictions are very preliminary.
Literally from the Help File of Occult: Note that the diameter is arbitrarily set at 10km, and the positional uncertainty is set at 3".

Regards,
Carlos

El 24/06/2021 a las 13:11, Carlos Perelló escribió:
Using Occult, these are the occultations calculated until 2035:

     Global summary of events - sorted by Date

     Date       U.T.    Diameter   Durn  Star  Mag-Drop Elon  %      Star         d Rely        Planet           Min        Moon     § ?    R.A. (J2000)  Dec.            Rec
   y   m  d    h   m     km   "   sec/m   mag   V    R     o Ill     No.            <1.4     No Name              D   Error Dist ill  ?    h  m   s      o  '   "           #
2028 Dec  5   14 40.8    10 0.001  0.55s 12.3  8.2  8.6   69     UCAC4 140-057616 s 0.85      0 C/2014 UN271 (Be 1.28 ±4.08   89  86      10 58 27.269 -62  2 45.99         0
2028 Dec 17    9 15.7    10 0.001  0.62s 12.1  8.5  8.6   74     UCAC4 137-051856 s 4.05      0 C/2014 UN271 (Be 0.94 ±4.05   82   2      10 59 19.973 -62 36 36.98         1
2029 Jan  1    4 45.9    10 0.001  0.69s 12.6  7.9  8.1   81     UCAC4 134-047703 s 0.80      0 C/2014 UN271 (Be 5.14 ±4.00   96 100      10 58 10.418 -63 14  0.21         2
2029 Jan 31    4 18.6    10 0.001  0.59s 11.3  9.1  9.4   96     TYC 8965-01100-1 s 0.75      0 C/2014 UN271 (Be 4.47 ±3.90   75  99      10 48 24.876 -63 53 48.38         3
2029 Feb  3   17 51.4    10 0.001  0.56s 12.1  8.4  8.7   98     UCAC4 131-040285 s 0.80      0 C/2014 UN271 (Be 6.44 ±3.88   57  74      10 46 42.995 -63 54  2.93         4

2029 Dec 29   10 30.9    10 0.001  0.96s  9.7 10.5 10.3   80     UCAC4 193-062412 w 11.1      0 C/2014 UN271 (Be 3.60 ±3.84   43  38      11 42 34.634 -51 35 50.30         5
2029 Dec 29   11  7.6    10 0.001  0.94s 11.3  9.0  8.7   80     UCAC4 193-062409 w 0.95      0 C/2014 UN271 (Be 3.92 ±3.84   43  38      11 42 33.976 -51 35 52.60         6
2030 Jan  1   10  7.4    10 0.001   2.1s 10.7  9.5 10.4   82     UCAC4 192-059604 v 1.05      0 C/2014 UN271 (Be 6.15 ±3.83   58  10      11 42 27.748 -51 41 17.99         7
2032 Dec  5   20 30.3    10 0.001  0.63s 12.4  8.1  8.3   60     UCAC4 384-061530 s 1.05      0 C/2014 UN271 (Be 0.01 ±4.08   98  11      12 42 35.336 -13 13 18.53         8
2032 Dec 23    3 55.7    10 0.001  1.03s 12.0  8.4  8.7   77     UCAC4 385-061483 s 1.35      0 C/2014 UN271 (Be 0.41 ±3.99   32  66      12 45  2.980 -13  2 35.43         9

2033 Feb  2   22 47.8    10 0.001  0.56s 12.3  8.1  8.4  119     UCAC4 391-057575 s 4.20      0 C/2014 UN271 (Be 2.88 ±3.78  162  13      12 44 16.057 -11 51 12.27        10
2035 May 17   10 40.8    10 0.001  0.53s 11.0 10.3 10.6  126     TYC 1449-00435-1 s 1.00      0 C/2014 UN271 (Be 0.47 ±4.41   18  80      12 48 17.694  15 55 10.51        11

Regards,
Carlos


El 24/06/2021 a las 12:41, andrew_j_walker via groups.io escribió:
Now we have a comet circular https://www.minorplanetcenter.net/mpec/K21/K21M83.html

Nice work with the extra observations from F51 and 568, and in the last few days!
Andrew


Re: 2014 UN271: cometary activity

Carlos Perelló
 

I forgot to say the list is filtered by StarMag <12.6. Obviously at this time the predictions are very preliminary.
Literally from the Help File of Occult: Note that the diameter is arbitrarily set at 10km, and the positional uncertainty is set at 3".

Regards,
Carlos

El 24/06/2021 a las 13:11, Carlos Perelló escribió:

Using Occult, these are the occultations calculated until 2035:

     Global summary of events - sorted by Date

     Date       U.T.    Diameter   Durn  Star  Mag-Drop Elon  %      Star         d Rely        Planet           Min        Moon     § ?    R.A. (J2000)  Dec.            Rec
   y   m  d    h   m     km   "   sec/m   mag   V    R     o Ill     No.            <1.4     No Name              D   Error Dist ill  ?    h  m   s      o  '   "           #
2028 Dec  5   14 40.8    10 0.001  0.55s 12.3  8.2  8.6   69     UCAC4 140-057616 s 0.85      0 C/2014 UN271 (Be 1.28 ±4.08   89  86      10 58 27.269 -62  2 45.99         0
2028 Dec 17    9 15.7    10 0.001  0.62s 12.1  8.5  8.6   74     UCAC4 137-051856 s 4.05      0 C/2014 UN271 (Be 0.94 ±4.05   82   2      10 59 19.973 -62 36 36.98         1
2029 Jan  1    4 45.9    10 0.001  0.69s 12.6  7.9  8.1   81     UCAC4 134-047703 s 0.80      0 C/2014 UN271 (Be 5.14 ±4.00   96 100      10 58 10.418 -63 14  0.21         2
2029 Jan 31    4 18.6    10 0.001  0.59s 11.3  9.1  9.4   96     TYC 8965-01100-1 s 0.75      0 C/2014 UN271 (Be 4.47 ±3.90   75  99      10 48 24.876 -63 53 48.38         3
2029 Feb  3   17 51.4    10 0.001  0.56s 12.1  8.4  8.7   98     UCAC4 131-040285 s 0.80      0 C/2014 UN271 (Be 6.44 ±3.88   57  74      10 46 42.995 -63 54  2.93         4

2029 Dec 29   10 30.9    10 0.001  0.96s  9.7 10.5 10.3   80     UCAC4 193-062412 w 11.1      0 C/2014 UN271 (Be 3.60 ±3.84   43  38      11 42 34.634 -51 35 50.30         5
2029 Dec 29   11  7.6    10 0.001  0.94s 11.3  9.0  8.7   80     UCAC4 193-062409 w 0.95      0 C/2014 UN271 (Be 3.92 ±3.84   43  38      11 42 33.976 -51 35 52.60         6
2030 Jan  1   10  7.4    10 0.001   2.1s 10.7  9.5 10.4   82     UCAC4 192-059604 v 1.05      0 C/2014 UN271 (Be 6.15 ±3.83   58  10      11 42 27.748 -51 41 17.99         7
2032 Dec  5   20 30.3    10 0.001  0.63s 12.4  8.1  8.3   60     UCAC4 384-061530 s 1.05      0 C/2014 UN271 (Be 0.01 ±4.08   98  11      12 42 35.336 -13 13 18.53         8
2032 Dec 23    3 55.7    10 0.001  1.03s 12.0  8.4  8.7   77     UCAC4 385-061483 s 1.35      0 C/2014 UN271 (Be 0.41 ±3.99   32  66      12 45  2.980 -13  2 35.43         9

2033 Feb  2   22 47.8    10 0.001  0.56s 12.3  8.1  8.4  119     UCAC4 391-057575 s 4.20      0 C/2014 UN271 (Be 2.88 ±3.78  162  13      12 44 16.057 -11 51 12.27        10
2035 May 17   10 40.8    10 0.001  0.53s 11.0 10.3 10.6  126     TYC 1449-00435-1 s 1.00      0 C/2014 UN271 (Be 0.47 ±4.41   18  80      12 48 17.694  15 55 10.51        11

Regards,
Carlos


El 24/06/2021 a las 12:41, andrew_j_walker via groups.io escribió:
Now we have a comet circular https://www.minorplanetcenter.net/mpec/K21/K21M83.html

Nice work with the extra observations from F51 and 568, and in the last few days!
Andrew



Re: 2014 UN271: cometary activity

Carlos Perelló
 

Using Occult, these are the occultations calculated until 2035:

     Global summary of events - sorted by Date

     Date       U.T.    Diameter   Durn  Star  Mag-Drop Elon  %      Star         d Rely        Planet           Min        Moon     § ?    R.A. (J2000)  Dec.            Rec
   y   m  d    h   m     km   "   sec/m   mag   V    R     o Ill     No.            <1.4     No Name              D   Error Dist ill  ?    h  m   s      o  '   "           #
2028 Dec  5   14 40.8    10 0.001  0.55s 12.3  8.2  8.6   69     UCAC4 140-057616 s 0.85      0 C/2014 UN271 (Be 1.28 ±4.08   89  86      10 58 27.269 -62  2 45.99         0
2028 Dec 17    9 15.7    10 0.001  0.62s 12.1  8.5  8.6   74     UCAC4 137-051856 s 4.05      0 C/2014 UN271 (Be 0.94 ±4.05   82   2      10 59 19.973 -62 36 36.98         1
2029 Jan  1    4 45.9    10 0.001  0.69s 12.6  7.9  8.1   81     UCAC4 134-047703 s 0.80      0 C/2014 UN271 (Be 5.14 ±4.00   96 100      10 58 10.418 -63 14  0.21         2
2029 Jan 31    4 18.6    10 0.001  0.59s 11.3  9.1  9.4   96     TYC 8965-01100-1 s 0.75      0 C/2014 UN271 (Be 4.47 ±3.90   75  99      10 48 24.876 -63 53 48.38         3
2029 Feb  3   17 51.4    10 0.001  0.56s 12.1  8.4  8.7   98     UCAC4 131-040285 s 0.80      0 C/2014 UN271 (Be 6.44 ±3.88   57  74      10 46 42.995 -63 54  2.93         4

2029 Dec 29   10 30.9    10 0.001  0.96s  9.7 10.5 10.3   80     UCAC4 193-062412 w 11.1      0 C/2014 UN271 (Be 3.60 ±3.84   43  38      11 42 34.634 -51 35 50.30         5
2029 Dec 29   11  7.6    10 0.001  0.94s 11.3  9.0  8.7   80     UCAC4 193-062409 w 0.95      0 C/2014 UN271 (Be 3.92 ±3.84   43  38      11 42 33.976 -51 35 52.60         6
2030 Jan  1   10  7.4    10 0.001   2.1s 10.7  9.5 10.4   82     UCAC4 192-059604 v 1.05      0 C/2014 UN271 (Be 6.15 ±3.83   58  10      11 42 27.748 -51 41 17.99         7
2032 Dec  5   20 30.3    10 0.001  0.63s 12.4  8.1  8.3   60     UCAC4 384-061530 s 1.05      0 C/2014 UN271 (Be 0.01 ±4.08   98  11      12 42 35.336 -13 13 18.53         8
2032 Dec 23    3 55.7    10 0.001  1.03s 12.0  8.4  8.7   77     UCAC4 385-061483 s 1.35      0 C/2014 UN271 (Be 0.41 ±3.99   32  66      12 45  2.980 -13  2 35.43         9

2033 Feb  2   22 47.8    10 0.001  0.56s 12.3  8.1  8.4  119     UCAC4 391-057575 s 4.20      0 C/2014 UN271 (Be 2.88 ±3.78  162  13      12 44 16.057 -11 51 12.27        10
2035 May 17   10 40.8    10 0.001  0.53s 11.0 10.3 10.6  126     TYC 1449-00435-1 s 1.00      0 C/2014 UN271 (Be 0.47 ±4.41   18  80      12 48 17.694  15 55 10.51        11

Regards,
Carlos


El 24/06/2021 a las 12:41, andrew_j_walker via groups.io escribió:

Now we have a comet circular https://www.minorplanetcenter.net/mpec/K21/K21M83.html

Nice work with the extra observations from F51 and 568, and in the last few days!
Andrew


Re: NEOWISE asteroid N0020xg recovered at magnitude 22.7 - how dark does that make it?

Marshall Eubanks
 

On 2021-06-28 17:49, Adrien Coffinet wrote:
Hi all,
Too few observations so far to be sure, but it looks like it could be
a quasi-satellite of Mars. It came 0.14 au away from the Earth in
Are these close approaches of Mars or of Earth?

Regards
Marshall

March 2014, soon after its discovery. The nominal orbit in JPL's SBDB
gives a close approach at 0.06 au in 2031, but the uncertainty is
large...
Adrien
Le lun. 28 juin 2021 21:20, Sam Deen via groups.io [1]
<planetaryscience@...> a écrit :

Hi Dave,
Thanks for your comments. The asteroid has been published as 2014
CS34 ( https://minorplanetcenter.net/mpec/K21/K21MA2.html )
Upon some further research it seemed that part of the huge
difference was that it has a very high-amplitude light curve: over
the 20 minutes of observations it cycled around three or four times
between magnitude ~22.1 and ~22.9. Furthermore, some earlier
PANSTARRS observations put it as a few tenths of a magnitude
brighter, so it looks like the actual disparity is more around 4.0
mag than 4.6 mag- but still sounds like a bit more than your usual
difference!
~Sam
On Sunday, June 27, 2021, 6:49:00 PM PDT, David Tholen
<tholen@...> wrote:

a factor of over 70 times dimmer than expected by WISE.
I've seen differences as large as 3 mag before; 4.6 mag is
probably a record. When doing follow-up of NEOWISE NEOCP
objects, we automatically assume at least 1.5 mag fainter
when choosing an exposure time, until a visible-light
observation is secured to clarify its visible magnitude.
Links:
------
[1] http://groups.io
[2] https://groups.io/g/mpml/message/36520
[3] https://groups.io/mt/83832995/2048683
[4] https://groups.io/g/mpml/post
[5] https://groups.io/g/mpml/editsub/2048683
[6] https://groups.io/g/mpml/unsub


Re: NEOWISE asteroid N0020xg recovered at magnitude 22.7 - how dark does that make it?

Adrien Coffinet
 

Hi all,

Too few observations so far to be sure, but it looks like it could be a quasi-satellite of Mars. It came 0.14 au away from the Earth in March 2014, soon after its discovery. The nominal orbit in JPL's SBDB gives a close approach at 0.06 au in 2031, but the uncertainty is large...

Adrien


Le lun. 28 juin 2021 21:20, Sam Deen via groups.io <planetaryscience=yahoo.com@groups.io> a écrit :
Hi Dave,

Thanks for your comments. The asteroid has been published as 2014 CS34 ( https://minorplanetcenter.net/mpec/K21/K21MA2.html )

Upon some further research it seemed that part of the huge difference was that it has a very high-amplitude light curve: over the 20 minutes of observations it cycled around three or four times between magnitude ~22.1 and ~22.9. Furthermore, some earlier PANSTARRS observations put it as a few tenths of a magnitude brighter, so it looks like the actual disparity is more around 4.0 mag than 4.6 mag- but still sounds like a bit more than your usual difference!

~Sam

On Sunday, June 27, 2021, 6:49:00 PM PDT, David Tholen <tholen@...> wrote:


> a factor of over 70 times dimmer than expected by WISE.


I've seen differences as large as 3 mag before; 4.6 mag is
probably a record.  When doing follow-up of NEOWISE NEOCP
objects, we automatically assume at least 1.5 mag fainter
when choosing an exposure time, until a visible-light
observation is secured to clarify its visible magnitude.






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