Topics

2019 LD2: the largest quasi-hilda comet


Sam Deen
 

Hi all,

I've been seeing some news going around recently that astronomers have discovered a 'new kind of asteroid':

https://www.hawaii.edu/news/2020/05/20/uh-atlas-discovers-new-asteroid/
https://phys.org/news/2020-05-atlas-telescope-first-of-its-kind-asteroid-comet-like.html

Well, I'm not entirely sure why the news has gotten this far without realizing it, but 2019 LD2 is not a Jupiter Trojan. In fact, by no means whatsoever is it in a remotely stable orbit, let alone in either of the trojan clouds. For one thing, 2019 LD2 is currently a mere 21 degrees ahead of Jupiter, and will not be getting further than 25-30 degrees from Jupiter during the course of its orbit for the next several years. Furthermore, running its orbit back even a couple of years shows why it suddenly appears as a comet: its very small close approach to Jupiter only in Februrary 2017!

JPL estimates that on 2017/02/17 2019 LD2 passed only 0.09204 +/- 0.00015 AU from Jupiter, and find_orb estimates a similar approach of 0.09204 +/- 0.0004 AU. Either way, its orbit prior to this looked nothing like its present orbit:

Perihelion 2016 Oct 28.530857 +/- 0.0988 TT = 12:44:26 (JD 2457690.030857)
Epoch 2010 Jan 1.0 TT = JDT 2455197.5 Ju: 0.2225 Sa: 0.0404
M 243.71551040 +/- 0.009 (J2000 ecliptic) Find_Orb
n 0.04665317 +/- 2.23e-6 Peri. 347.17400 +/- 0.011
a 7.64214401 +/- 0.000244 Node 196.56492 +/- 0.0023
e 0.2645611 +/- 3.54e-5 Incl. 11.13635 +/- 0.0019
P 21.13 H 12.4 G 0.15 U 4.1
q 5.62032998 +/- 0.000107 Q 9.66395804 +/- 0.000574
119 of 124 observations 2018 May 21-2020 Apr. 24; mean residual 0".35

As a typical-looking centaur, 2019 LD2 is almost certainly an ex-long period comet that only in 2017 achieved a perihelion low enough to start noticeably outgassing. Interestingly, due to its semi-Jupiter resonant orbit, it will make another approach to Jupiter on 2028/05/13 of 0.11934 +/- 0.00020 AU, which will once again alter the comet's orbit to a fairly inactive one:

Perihelion 2027 Oct 6.382740 +/- 1.21 TT = 9:11:08 (JD 2461684.882740)
Epoch 2035 Jan 1.0 TT = JDT 2464328.5 Ju: 0.0614 Find_Orb
M 146.78471583 +/- 0.10 (J2000 ecliptic)
n 0.05552419 +/- 1.38e-5 Peri. 1.16326 +/- 0.10
a 6.80478713 +/- 0.00113 Node 157.85564 +/- 0.0030
e 0.2137156 +/- 9.19e-5 Incl. 10.46415 +/- 0.0022
P 17.75 H 12.4 G 0.15 U 5.4
q 5.35049744 +/- 0.000265 Q 8.25907681 +/- 0.00199
119 of 124 observations 2018 May 21-2020 Apr. 24; mean residual 0".35

Lastly, and by far most interestingly of all, in January 2063, it will make a VERY close approach to Jupiter- 3.09 +/- 1.48 million kilometers (-0.8 sigma to passing in between the orbits of Ganymede and Callisto). I'm still not very good with satellite ephemerides but it seems to me as if the nominal orbit has it passing quite close to Callisto. Due to the large (relatively speaking) uncertainty on the exact details of that close approach, it's impossible to say exactly what its orbit will look like after, but needless to say the January 2063 approach should definitely be interesting.

Also, based on negative precovery images from May 2017, the nucleus of the comet is less than H=15.3, corresponding to a maximum size of ~4-8 km

~Sam


tony873004
 

I saw this story this morning, and wanted to make a simulation to post on Twitter. But my effort showed what you said. It's not Trojan, Greek, or even Hilda. It regularly makes very close passes to Jupiter (perhaps why its outgassing), and often approaches the orbit of Saturn.
Here's my Tweet, with a picture, and 2 simulations that will run in your browser: 2019 LD2, Greeks, Trojans, Hildas, and the 2nd sim is 2019 LD2 only. Both sims run in a rotating frame with Jupiter's period.

On Thu, May 21, 2020 at 6:41 PM Sam Deen via groups.io <planetaryscience=yahoo.com@groups.io> wrote:
Hi all,

I've been seeing some news going around recently that astronomers have discovered a 'new kind of asteroid':

https://www.hawaii.edu/news/2020/05/20/uh-atlas-discovers-new-asteroid/
https://phys.org/news/2020-05-atlas-telescope-first-of-its-kind-asteroid-comet-like.html

Well, I'm not entirely sure why the news has gotten this far without realizing it, but 2019 LD2 is not a Jupiter Trojan. In fact, by no means whatsoever is it in a remotely stable orbit, let alone in either of the trojan clouds. For one thing, 2019 LD2 is currently a mere 21 degrees ahead of Jupiter, and will not be getting further than 25-30 degrees from Jupiter during the course of its orbit for the next several years. Furthermore, running its orbit back even a couple of years shows why it suddenly appears as a comet: its very small close approach to Jupiter only in Februrary 2017!

JPL estimates that on 2017/02/17 2019 LD2 passed only 0.09204 +/- 0.00015 AU from Jupiter, and find_orb estimates a similar approach of 0.09204 +/- 0.0004 AU. Either way, its orbit prior to this looked nothing like its present orbit:

   Perihelion 2016 Oct 28.530857 +/- 0.0988 TT = 12:44:26 (JD 2457690.030857)
Epoch 2010 Jan  1.0 TT = JDT 2455197.5   Ju: 0.2225   Sa: 0.0404
M 243.71551040 +/- 0.009            (J2000 ecliptic)          Find_Orb
n   0.04665317 +/- 2.23e-6          Peri.  347.17400 +/- 0.011
a   7.64214401 +/- 0.000244         Node   196.56492 +/- 0.0023
e   0.2645611 +/- 3.54e-5           Incl.   11.13635 +/- 0.0019
P  21.13                   H 12.4   G  0.15   U  4.1 
q 5.62032998 +/- 0.000107    Q 9.66395804 +/- 0.000574
119 of 124 observations 2018 May 21-2020 Apr. 24; mean residual 0".35

As a typical-looking centaur, 2019 LD2 is almost certainly an ex-long period comet that only in 2017 achieved a perihelion low enough to start noticeably outgassing. Interestingly, due to its semi-Jupiter resonant orbit, it will make another approach to Jupiter on 2028/05/13 of 0.11934 +/- 0.00020 AU, which will once again alter the comet's orbit to a fairly inactive one:

   Perihelion 2027 Oct 6.382740 +/- 1.21 TT =  9:11:08 (JD 2461684.882740)
Epoch 2035 Jan  1.0 TT = JDT 2464328.5   Ju: 0.0614           Find_Orb
M 146.78471583 +/- 0.10             (J2000 ecliptic)
n   0.05552419 +/- 1.38e-5          Peri.    1.16326 +/- 0.10
a   6.80478713 +/- 0.00113          Node   157.85564 +/- 0.0030
e   0.2137156 +/- 9.19e-5           Incl.   10.46415 +/- 0.0022
P  17.75                   H 12.4   G  0.15   U  5.4 
q 5.35049744 +/- 0.000265    Q 8.25907681 +/- 0.00199
119 of 124 observations 2018 May 21-2020 Apr. 24; mean residual 0".35

Lastly, and by far most interestingly of all, in January 2063, it will make a VERY close approach to Jupiter- 3.09 +/- 1.48 million kilometers (-0.8 sigma to passing in between the orbits of Ganymede and Callisto). I'm still not very good with satellite ephemerides but it seems to me as if the nominal orbit has it passing quite close to Callisto. Due to the large (relatively speaking) uncertainty on the exact details of that close approach, it's impossible to say exactly what its orbit will look like after, but needless to say the January 2063 approach should definitely be interesting.

Also, based on negative precovery images from May 2017, the nucleus of the comet is less than H=15.3, corresponding to a maximum size of ~4-8 km

~Sam




andrew_j_walker@...
 

Yes, to be a member of one of these families you would hope for at least a scintilla of stability!
Otherwise the claims they make are like shouting in the wind.

Andrew


Marshall Eubanks
 

On 2020-05-21 21:41, Sam Deen via groups.io wrote:
Hi all,
I've been seeing some news going around recently that astronomers have
discovered a 'new kind of asteroid':
https://www.hawaii.edu/news/2020/05/20/uh-atlas-discovers-new-asteroid/
https://phys.org/news/2020-05-atlas-telescope-first-of-its-kind-asteroid-comet-like.html
Well, I'm not entirely sure why the news has gotten this far without
realizing it, but 2019 LD2 is not a Jupiter Trojan. In fact, by no
means whatsoever is it in a remotely stable orbit, let alone in either
of the trojan clouds. For one thing, 2019 LD2 is currently a mere 21
degrees ahead of Jupiter, and will not be getting further than 25-30
degrees from Jupiter during the course of its orbit for the next
several years. Furthermore, running its orbit back even a couple of
years shows why it suddenly appears as a comet: its very small close
approach to Jupiter only in Februrary 2017!
Here is a nice visualization of its complicated orbit from Tony Dunn

https://twitter.com/tony873004/status/1263653962999197696

JPL estimates that on 2017/02/17 2019 LD2 passed only 0.09204 +/-
0.00015 AU from Jupiter, and find_orb estimates a similar approach of
0.09204 +/- 0.0004 AU. Either way, its orbit prior to this looked
nothing like its present orbit:
Perihelion 2016 Oct 28.530857 +/- 0.0988 TT = 12:44:26 (JD 2457690.030857)
Epoch 2010 Jan 1.0 TT = JDT 2455197.5 Ju: 0.2225 Sa: 0.0404
M 243.71551040 +/- 0.009 (J2000 ecliptic) Find_Orb
n 0.04665317 +/- 2.23e-6 Peri. 347.17400 +/- 0.011
a 7.64214401 +/- 0.000244 Node 196.56492 +/- 0.0023
e 0.2645611 +/- 3.54e-5 Incl. 11.13635 +/- 0.0019
P 21.13 H 12.4 G 0.15 U 4.1
q 5.62032998 +/- 0.000107 Q 9.66395804 +/- 0.000574
119 of 124 observations 2018 May 21-2020 Apr. 24; mean residual 0".35
As a typical-looking centaur, 2019 LD2 is almost certainly an ex-long
period comet that only in 2017 achieved a perihelion low enough to
start noticeably outgassing. Interestingly, due to its semi-Jupiter
resonant orbit, it will make another approach to Jupiter on 2028/05/13
of 0.11934 +/- 0.00020 AU, which will once again alter the comet's
orbit to a fairly inactive one:
Perihelion 2027 Oct 6.382740 +/- 1.21 TT = 9:11:08 (JD 2461684.882740)
Epoch 2035 Jan 1.0 TT = JDT 2464328.5 Ju: 0.0614 Find_Orb
M 146.78471583 +/- 0.10 (J2000 ecliptic)
n 0.05552419 +/- 1.38e-5 Peri. 1.16326 +/- 0.10
a 6.80478713 +/- 0.00113 Node 157.85564 +/- 0.0030
e 0.2137156 +/- 9.19e-5 Incl. 10.46415 +/- 0.0022
P 17.75 H 12.4 G 0.15 U 5.4
q 5.35049744 +/- 0.000265 Q 8.25907681 +/- 0.00199
119 of 124 observations 2018 May 21-2020 Apr. 24; mean residual 0".35
Lastly, and by far most interestingly of all, in January 2063, it will
make a VERY close approach to Jupiter- 3.09 +/- 1.48 million
kilometers (-0.8 sigma to passing in between the orbits of Ganymede
and Callisto). I'm still not very good with satellite ephemerides but
it seems to me as if the nominal orbit has it passing quite close to
Callisto. Due to the large (relatively speaking) uncertainty on the
exact details of that close approach, it's impossible to say exactly
what its orbit will look like after, but needless to say the January
2063 approach should definitely be interesting.
Also, based on negative precovery images from May 2017, the nucleus of
the comet is less than H=15.3, corresponding to a maximum size of ~4-8
km
~Sam


Larry Denneau
 

Hi Folks,

We are reviewing the dynamical results presented here by Sam Deen and will likely issue a correction/retraction today or tomorrow regarding 2019 LD2 being a member of the Jupiter Trojan population.

Aloha,
Larry

--
Larry Denneau
ATLAS Project


On Thu, May 21, 2020 at 3:41 PM Sam Deen via groups.io <planetaryscience=yahoo.com@groups.io> wrote:
Hi all,

I've been seeing some news going around recently that astronomers have discovered a 'new kind of asteroid':

https://www.hawaii.edu/news/2020/05/20/uh-atlas-discovers-new-asteroid/
https://phys.org/news/2020-05-atlas-telescope-first-of-its-kind-asteroid-comet-like.html

Well, I'm not entirely sure why the news has gotten this far without realizing it, but 2019 LD2 is not a Jupiter Trojan. In fact, by no means whatsoever is it in a remotely stable orbit, let alone in either of the trojan clouds. For one thing, 2019 LD2 is currently a mere 21 degrees ahead of Jupiter, and will not be getting further than 25-30 degrees from Jupiter during the course of its orbit for the next several years. Furthermore, running its orbit back even a couple of years shows why it suddenly appears as a comet: its very small close approach to Jupiter only in Februrary 2017!

JPL estimates that on 2017/02/17 2019 LD2 passed only 0.09204 +/- 0.00015 AU from Jupiter, and find_orb estimates a similar approach of 0.09204 +/- 0.0004 AU. Either way, its orbit prior to this looked nothing like its present orbit:

   Perihelion 2016 Oct 28.530857 +/- 0.0988 TT = 12:44:26 (JD 2457690.030857)
Epoch 2010 Jan  1.0 TT = JDT 2455197.5   Ju: 0.2225   Sa: 0.0404
M 243.71551040 +/- 0.009            (J2000 ecliptic)          Find_Orb
n   0.04665317 +/- 2.23e-6          Peri.  347.17400 +/- 0.011
a   7.64214401 +/- 0.000244         Node   196.56492 +/- 0.0023
e   0.2645611 +/- 3.54e-5           Incl.   11.13635 +/- 0.0019
P  21.13                   H 12.4   G  0.15   U  4.1 
q 5.62032998 +/- 0.000107    Q 9.66395804 +/- 0.000574
119 of 124 observations 2018 May 21-2020 Apr. 24; mean residual 0".35

As a typical-looking centaur, 2019 LD2 is almost certainly an ex-long period comet that only in 2017 achieved a perihelion low enough to start noticeably outgassing. Interestingly, due to its semi-Jupiter resonant orbit, it will make another approach to Jupiter on 2028/05/13 of 0.11934 +/- 0.00020 AU, which will once again alter the comet's orbit to a fairly inactive one:

   Perihelion 2027 Oct 6.382740 +/- 1.21 TT =  9:11:08 (JD 2461684.882740)
Epoch 2035 Jan  1.0 TT = JDT 2464328.5   Ju: 0.0614           Find_Orb
M 146.78471583 +/- 0.10             (J2000 ecliptic)
n   0.05552419 +/- 1.38e-5          Peri.    1.16326 +/- 0.10
a   6.80478713 +/- 0.00113          Node   157.85564 +/- 0.0030
e   0.2137156 +/- 9.19e-5           Incl.   10.46415 +/- 0.0022
P  17.75                   H 12.4   G  0.15   U  5.4 
q 5.35049744 +/- 0.000265    Q 8.25907681 +/- 0.00199
119 of 124 observations 2018 May 21-2020 Apr. 24; mean residual 0".35

Lastly, and by far most interestingly of all, in January 2063, it will make a VERY close approach to Jupiter- 3.09 +/- 1.48 million kilometers (-0.8 sigma to passing in between the orbits of Ganymede and Callisto). I'm still not very good with satellite ephemerides but it seems to me as if the nominal orbit has it passing quite close to Callisto. Due to the large (relatively speaking) uncertainty on the exact details of that close approach, it's impossible to say exactly what its orbit will look like after, but needless to say the January 2063 approach should definitely be interesting.

Also, based on negative precovery images from May 2017, the nucleus of the comet is less than H=15.3, corresponding to a maximum size of ~4-8 km

~Sam




alessandro odasso
 

the object is now known as P/2019 LD2 (ATLAS)

More on its cometary origin here:
https://odassoastro.blogspot.com/2020/05/comet-p2019-ld2-atlas.html

KInd Regards,
Alessandro Odasso


Marshall Eubanks
 

On 2020-05-24 05:49, alessandro odasso wrote:
the object is now known as P/2019 LD2 (ATLAS)
More on its cometary origin here:
https://odassoastro.blogspot.com/2020/05/comet-p2019-ld2-atlas.html
Do you actually think this is a captured interstellar object?

What would be its most likely incoming radiant (i.e., where would it be coming from "at infinity")?

Regards
Marshall Eubanks

KInd Regards,
Alessandro Odasso
Links:
------
[1] https://groups.io/g/mpml/message/35549
[2] https://groups.io/mt/74390462/2048683
[3] https://groups.io/g/mpml/post
[4] https://groups.io/g/mpml/editsub/2048683
[5] https://groups.io/g/mpml/unsub


alessandro odasso
 

this is likely a simulation glitch ... 100 days before the hyperbolic trajectory the eccentricity is no longer greater than 1 !
a e i peri node long
311100.5 11.10955 0.56037 12.7835 207.0631 179.7592 26.8223
311000.5 12.17985 0.599077 13.1885 206.6135 180.4985 27.112
310900.5 -6.12701 1.813375 2.8379 213.9255 160.4411 14.3666
310800.5 126.90366 0.960378 4.4906 347.4277 20.2166 7.6443
310700.5 58.4381 0.913926 4.4251 347.0157 20.7539 7.7696
310600.5 48.95964 0.897233 4.3941 346.7163 21.1435 7.8598


Kind Regards
alessandro odasso


From: tme@... <tme@...>
Sent: Sunday, May 24, 2020 2:55 PM
To: alessandro odasso <alessandro_odasso@...>
Cc: mpml@groups.io <mpml@groups.io>
Subject: Re: {MPML} 2019 LD2: the largest quasi-hilda comet
 
On 2020-05-24 05:49, alessandro odasso wrote:
> the object is now known as P/2019 LD2 (ATLAS)
>
> More on its cometary origin here:
> https://odassoastro.blogspot.com/2020/05/comet-p2019-ld2-atlas.html
>

Do you actually think this is a captured interstellar object?

What would be its most likely incoming radiant (i.e., where would it be
coming from "at infinity")?

Regards
Marshall Eubanks

> KInd Regards,
> Alessandro Odasso >
> Links:
> ------
> [1] https://groups.io/g/mpml/message/35549
> [2] https://groups.io/mt/74390462/2048683
> [3] https://groups.io/g/mpml/post
> [4] https://groups.io/g/mpml/editsub/2048683
> [5] https://groups.io/g/mpml/unsub


Jean Meeus
 

When one calculates the HELIOCENTRIC orbit near the time the object is close to Jupiter, one obtains a hyperbolic orbit, that however is meaningless because at that instant the object is attracted more by Jupiter than by the Sun.

Jean Meeus


On Sun, 24 May 2020 at 16:43, alessandro odasso <alessandro_odasso@...> wrote:
this is likely a simulation glitch ... 100 days before the hyperbolic trajectory the eccentricity is no longer greater than 1 !
a e i peri node long
311100.5 11.10955 0.56037 12.7835 207.0631 179.7592 26.8223
311000.5 12.17985 0.599077 13.1885 206.6135 180.4985 27.112
310900.5 -6.12701 1.813375 2.8379 213.9255 160.4411 14.3666
310800.5 126.90366 0.960378 4.4906 347.4277 20.2166 7.6443
310700.5 58.4381 0.913926 4.4251 347.0157 20.7539 7.7696
310600.5 48.95964 0.897233 4.3941 346.7163 21.1435 7.8598


Kind Regards
alessandro odasso


From: tme@... <tme@...>
Sent: Sunday, May 24, 2020 2:55 PM
To: alessandro odasso <alessandro_odasso@...>
Cc: mpml@groups.io <mpml@groups.io>
Subject: Re: {MPML} 2019 LD2: the largest quasi-hilda comet
 
On 2020-05-24 05:49, alessandro odasso wrote:
> the object is now known as P/2019 LD2 (ATLAS)
>
> More on its cometary origin here:
> https://odassoastro.blogspot.com/2020/05/comet-p2019-ld2-atlas.html
>

Do you actually think this is a captured interstellar object?

What would be its most likely incoming radiant (i.e., where would it be
coming from "at infinity")?

Regards
Marshall Eubanks

> KInd Regards,
> Alessandro Odasso >
> Links:
> ------
> [1] https://groups.io/g/mpml/message/35549
> [2] https://groups.io/mt/74390462/2048683
> [3] https://groups.io/g/mpml/post
> [4] https://groups.io/g/mpml/editsub/2048683
> [5] https://groups.io/g/mpml/unsub


alessandro odasso
 

Thanks to Marshall Eubanks  for his doubt  and thanks to Jean Meeus for explaining what is going on here.

 

I updated the explanation on the blog.

 

Cheers

Alessandro

 

From: Jean Meeus
Sent: 24 May 2020 17:33
To: alessandro odasso
Cc: tme@...; mpml@groups.io
Subject: Re: {MPML} 2019 LD2: the largest quasi-hilda comet

 

When one calculates the HELIOCENTRIC orbit near the time the object is close to Jupiter, one obtains a hyperbolic orbit, that however is meaningless because at that instant the object is attracted more by Jupiter than by the Sun.

 

Jean Meeus

 

 

On Sun, 24 May 2020 at 16:43, alessandro odasso <alessandro_odasso@...> wrote:

this is likely a simulation glitch ... 100 days before the hyperbolic trajectory the eccentricity is no longer greater than 1 !

a

e

i

peri

node

long

311100.5

11.10955

0.56037

12.7835

207.0631

179.7592

26.8223

311000.5

12.17985

0.599077

13.1885

206.6135

180.4985

27.112

310900.5

-6.12701

1.813375

2.8379

213.9255

160.4411

14.3666

310800.5

126.90366

0.960378

4.4906

347.4277

20.2166

7.6443

310700.5

58.4381

0.913926

4.4251

347.0157

20.7539

7.7696

310600.5

48.95964

0.897233

4.3941

346.7163

21.1435

7.8598

 

 

Kind Regards

alessandro odasso

 

From: tme@... <tme@...>
Sent: Sunday, May 24, 2020 2:55 PM
To: alessandro odasso <alessandro_odasso@...>
Cc: mpml@groups.io <mpml@groups.io>
Subject: Re: {MPML} 2019 LD2: the largest quasi-hilda comet

 

On 2020-05-24 05:49, alessandro odasso wrote:
> the object is now known as P/2019 LD2 (ATLAS)
>
> More on its cometary origin here:
> https://odassoastro.blogspot.com/2020/05/comet-p2019-ld2-atlas.html
>

Do you actually think this is a captured interstellar object?

What would be its most likely incoming radiant (i.e., where would it be
coming from "at infinity")?

Regards
Marshall Eubanks

> KInd Regards,
> Alessandro Odasso >
> Links:
> ------
> [1] https://groups.io/g/mpml/message/35549
> [2] https://groups.io/mt/74390462/2048683
> [3] https://groups.io/g/mpml/post
> [4] https://groups.io/g/mpml/editsub/2048683
> [5] https://groups.io/g/mpml/unsub

 


David Moore(Ireland)
 

This is getting ridiculous.

Just ran JPL HORIZONS and the elset they are using is still only from an arc April 10-28. 
That's only an 18 day arc at this late stage,
but more importantly that's not using any observations in nearly a month,
and for such a bright comet!

I used to think JPL HORIZONS was the most accurate and professional source of positions.

But now I am not so sure.

David Moore BSc FRAS
Editor, Astronomy Ireland magazine
editor@...


On Sunday 24 May 2020, 16:33:39 GMT+1, Jean Meeus <jmeeus@...> wrote:


When one calculates the HELIOCENTRIC orbit near the time the object is close to Jupiter, one obtains a hyperbolic orbit, that however is meaningless because at that instant the object is attracted more by Jupiter than by the Sun.

Jean Meeus


On Sun, 24 May 2020 at 16:43, alessandro odasso <alessandro_odasso@...> wrote:
this is likely a simulation glitch ... 100 days before the hyperbolic trajectory the eccentricity is no longer greater than 1 !
a e i peri node long
311100.5 11.10955 0.56037 12.7835 207.0631 179.7592 26.8223
311000.5 12.17985 0.599077 13.1885 206.6135 180.4985 27.112
310900.5 -6.12701 1.813375 2.8379 213.9255 160.4411 14.3666
310800.5 126.90366 0.960378 4.4906 347.4277 20.2166 7.6443
310700.5 58.4381 0.913926 4.4251 347.0157 20.7539 7.7696
310600.5 48.95964 0.897233 4.3941 346.7163 21.1435 7.8598


Kind Regards
alessandro odasso


From: tme@... <tme@...>
Sent: Sunday, May 24, 2020 2:55 PM
To: alessandro odasso <alessandro_odasso@...>
Cc: mpml@groups.io <mpml@groups.io>
Subject: Re: {MPML} 2019 LD2: the largest quasi-hilda comet
 
On 2020-05-24 05:49, alessandro odasso wrote:
> the object is now known as P/2019 LD2 (ATLAS)
>
> More on its cometary origin here:
> https://odassoastro.blogspot.com/2020/05/comet-p2019-ld2-atlas.html
>

Do you actually think this is a captured interstellar object?

What would be its most likely incoming radiant (i.e., where would it be
coming from "at infinity")?

Regards
Marshall Eubanks

> KInd Regards,
> Alessandro Odasso >
> Links:
> ------
> [1] https://groups.io/g/mpml/message/35549
> [2] https://groups.io/mt/74390462/2048683
> [3] https://groups.io/g/mpml/post
> [4] https://groups.io/g/mpml/editsub/2048683
> [5] https://groups.io/g/mpml/unsub


Peter Birtwhistle
 

David,

via the Horizons web interface it looks OK? :

JPL/HORIZONS                 ATLAS (P/2019 LD2) 2020-May-24 11:52:57
Soln.date: 2020-May-22_18:42:46    # obs: 136 (2018-2020)
1: soln ref.= JPL#8, data arc: 2018-05-21 to 2020-05-19


Peter
J95

On 24/05/2020 19:22, David Moore(Ireland) via groups.io wrote:
This is getting ridiculous.

Just ran JPL HORIZONS and the elset they are using is still only from an arc April 10-28.
That's only an 18 day arc at this late stage,
but more importantly that's not using any observations in nearly a month,
and for such a bright comet!

I used to think JPL HORIZONS was the most accurate and professional source of positions.

But now I am not so sure.

David Moore BSc FRAS
Editor, Astronomy Ireland magazine
editor@...


On Sunday 24 May 2020, 16:33:39 GMT+1, Jean Meeus <jmeeus@...> wrote:


When one calculates the HELIOCENTRIC orbit near the time the object is close to Jupiter, one obtains a hyperbolic orbit, that however is meaningless because at that instant the object is attracted more by Jupiter than by the Sun.

Jean Meeus


On Sun, 24 May 2020 at 16:43, alessandro odasso <alessandro_odasso@... <mailto:alessandro_odasso@...>> wrote:

this is likely a simulation glitch ... 100 days before the
hyperbolic trajectory the eccentricity is no longer greater than 1 !

a e i peri node long
311100.5 11.10955 0.56037 12.7835 207.0631 179.7592 26.8223
311000.5 12.17985 0.599077 13.1885 206.6135 180.4985 27.112
310900.5 -6.12701 1.813375 2.8379 213.9255 160.4411 14.3666
310800.5 126.90366 0.960378 4.4906 347.4277 20.2166 7.6443
310700.5 58.4381 0.913926 4.4251 347.0157 20.7539 7.7696
310600.5 48.95964 0.897233 4.3941 346.7163 21.1435 7.8598



Kind Regards
alessandro odasso


Bill J. Gray
 

Hi David,

Hmmm... I just tried it, and JPL (accurately) remapped 2019 LD2
to its new P/2019 LD2 designation. The object info at the top of the
ephemeris says 136 observations from 2018 to 2020.

Generally speaking, when I see that I'm not getting results that
match Horizons, I assume it's probably an error on my end. And
generally speaking, that has turned out to be correct. I think
your original thinking was on target.

-- Bill

On 5/24/20 2:22 PM, David Moore(Ireland) via groups.io wrote:
This is getting ridiculous.
Just ran JPL HORIZONS and the elset they are using is still only from an arc April 10-28.
That's only an 18 day arc at this late stage,
but more importantly that's not using any observations in nearly a month,
and for such a bright comet!
I used to think JPL HORIZONS was the most accurate and professional source of positions.
But now I am not so sure.
David Moore BSc FRAS
Editor, Astronomy Ireland magazine
editor@...
On Sunday 24 May 2020, 16:33:39 GMT+1, Jean Meeus <jmeeus@...> wrote:
When one calculates the HELIOCENTRIC orbit near the time the object is close to Jupiter, one obtains a hyperbolic orbit, that however is meaningless because at that instant the object is attracted more by Jupiter than by the Sun.
Jean Meeus
On Sun, 24 May 2020 at 16:43, alessandro odasso <alessandro_odasso@... <mailto:alessandro_odasso@...>> wrote:
this is likely a simulation glitch ... 100 days before the hyperbolic trajectory the eccentricity is no longer greater than 1 !
a e i peri node long
311100.5 11.10955 0.56037 12.7835 207.0631 179.7592 26.8223
311000.5 12.17985 0.599077 13.1885 206.6135 180.4985 27.112
310900.5 -6.12701 1.813375 2.8379 213.9255 160.4411 14.3666
310800.5 126.90366 0.960378 4.4906 347.4277 20.2166 7.6443
310700.5 58.4381 0.913926 4.4251 347.0157 20.7539 7.7696
310600.5 48.95964 0.897233 4.3941 346.7163 21.1435 7.8598
Kind Regards
alessandro odasso
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
*From:* @TMEubanks <mailto:@TMEubanks> <@TMEubanks <mailto:@TMEubanks>>
*Sent:* Sunday, May 24, 2020 2:55 PM
*To:* alessandro odasso <alessandro_odasso@... <mailto:alessandro_odasso@...>>
*Cc:* mpml@groups.io <mailto:mpml@groups.io> <mpml@groups.io <mailto:mpml@groups.io>>
*Subject:* Re: {MPML} 2019 LD2: the largest quasi-hilda comet
On 2020-05-24 05:49, alessandro odasso wrote:
> the object is now known as P/2019 LD2 (ATLAS)
>
> More on its cometary origin here:
> https://odassoastro.blogspot.com/2020/05/comet-p2019-ld2-atlas.html
>
Do you actually think this is a captured interstellar object?
What would be its most likely incoming radiant (i.e., where would it be
coming from "at infinity")?
Regards
Marshall Eubanks

> KInd Regards,
> Alessandro Odasso >
> Links:
> ------
> [1] https://groups.io/g/mpml/message/35549
> [2] https://groups.io/mt/74390462/2048683
> [3] https://groups.io/g/mpml/post
> [4] https://groups.io/g/mpml/editsub/2048683
> [5] https://groups.io/g/mpml/unsub


tony873004
 

Some fun meaningless trivia is that the heliocentric orbits of the Galilean Moons are usually hyperbolic. If Jupiter magically disappeared, depending on where the moons were in their orbits, they could do anything from nosedive into the Sun (Io, Europa) or inner solar system, or escape into interstellar space.


On Sun, May 24, 2020 at 8:33 AM Jean Meeus <jmeeus@...> wrote:
When one calculates the HELIOCENTRIC orbit near the time the object is close to Jupiter, one obtains a hyperbolic orbit, that however is meaningless because at that instant the object is attracted more by Jupiter than by the Sun.

Jean Meeus


On Sun, 24 May 2020 at 16:43, alessandro odasso <alessandro_odasso@...> wrote:
this is likely a simulation glitch ... 100 days before the hyperbolic trajectory the eccentricity is no longer greater than 1 !
a e i peri node long
311100.5 11.10955 0.56037 12.7835 207.0631 179.7592 26.8223
311000.5 12.17985 0.599077 13.1885 206.6135 180.4985 27.112
310900.5 -6.12701 1.813375 2.8379 213.9255 160.4411 14.3666
310800.5 126.90366 0.960378 4.4906 347.4277 20.2166 7.6443
310700.5 58.4381 0.913926 4.4251 347.0157 20.7539 7.7696
310600.5 48.95964 0.897233 4.3941 346.7163 21.1435 7.8598


Kind Regards
alessandro odasso


From: tme@... <tme@...>
Sent: Sunday, May 24, 2020 2:55 PM
To: alessandro odasso <alessandro_odasso@...>
Cc: mpml@groups.io <mpml@groups.io>
Subject: Re: {MPML} 2019 LD2: the largest quasi-hilda comet
 
On 2020-05-24 05:49, alessandro odasso wrote:
> the object is now known as P/2019 LD2 (ATLAS)
>
> More on its cometary origin here:
> https://odassoastro.blogspot.com/2020/05/comet-p2019-ld2-atlas.html
>

Do you actually think this is a captured interstellar object?

What would be its most likely incoming radiant (i.e., where would it be
coming from "at infinity")?

Regards
Marshall Eubanks

> KInd Regards,
> Alessandro Odasso >
> Links:
> ------
> [1] https://groups.io/g/mpml/message/35549
> [2] https://groups.io/mt/74390462/2048683
> [3] https://groups.io/g/mpml/post
> [4] https://groups.io/g/mpml/editsub/2048683
> [5] https://groups.io/g/mpml/unsub


David Moore(Ireland)
 

Oh sorry everyone I meant C/2020 F8 (SWAN)!



On Sunday 24 May 2020, 20:00:05 GMT+1, Bill J. Gray <pluto@...> wrote:


Hi David,

    Hmmm... I just tried it,  and JPL (accurately) remapped 2019 LD2
to its new P/2019 LD2 designation.  The object info at the top of the
ephemeris says 136 observations from 2018 to 2020.

    Generally speaking,  when I see that I'm not getting results that
match Horizons,  I assume it's probably an error on my end.  And
generally speaking,  that has turned out to be correct.  I think
your original thinking was on target.

-- Bill

On 5/24/20 2:22 PM, David Moore(Ireland) via groups.io wrote:
> This is getting ridiculous.
>
> Just ran JPL HORIZONS and the elset they are using is still only from an arc April 10-28.
> That's only an 18 day arc at this late stage,
> but more importantly that's not using any observations in nearly a month,
> and for such a bright comet!
>
> I used to think JPL HORIZONS was the most accurate and professional source of positions.
>
> But now I am not so sure.
>
> David Moore BSc FRAS
> Editor, Astronomy Ireland magazine
> editor@...
>
>
> On Sunday 24 May 2020, 16:33:39 GMT+1, Jean Meeus <jmeeus@...> wrote:
>
>
> When one calculates the HELIOCENTRIC orbit near the time the object is close to Jupiter, one obtains a hyperbolic orbit, that however is meaningless because at that instant the object is attracted more by Jupiter than by the Sun.
>
> Jean Meeus
>
>
> On Sun, 24 May 2020 at 16:43, alessandro odasso <alessandro_odasso@... <mailto:alessandro_odasso@...>> wrote:
>
>    this is likely a simulation glitch ... 100 days before the hyperbolic trajectory the eccentricity is no longer greater than 1 !
>        a    e    i    peri    node    long
>    311100.5    11.10955    0.56037    12.7835    207.0631    179.7592    26.8223
>    311000.5    12.17985    0.599077    13.1885    206.6135    180.4985    27.112
>    310900.5    -6.12701    1.813375    2.8379    213.9255    160.4411    14.3666
>    310800.5    126.90366    0.960378    4.4906    347.4277    20.2166    7.6443
>    310700.5    58.4381    0.913926    4.4251    347.0157    20.7539    7.7696
>    310600.5    48.95964    0.897233    4.3941    346.7163    21.1435    7.8598
>
>
>
>    Kind Regards
>    alessandro odasso
>
>    ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
>    *From:* tme@... <mailto:tme@...> <tme@... <mailto:tme@...>>
>    *Sent:* Sunday, May 24, 2020 2:55 PM
>    *To:* alessandro odasso <alessandro_odasso@... <mailto:alessandro_odasso@...>>
>    *Cc:* mpml@groups.io <mailto:mpml@groups.io> <mpml@groups.io <mailto:mpml@groups.io>>
>    *Subject:* Re: {MPML} 2019 LD2: the largest quasi-hilda comet
>    On 2020-05-24 05:49, alessandro odasso wrote:
>      > the object is now known as P/2019 LD2 (ATLAS)
>      >
>      > More on its cometary origin here:
>      > https://odassoastro.blogspot.com/2020/05/comet-p2019-ld2-atlas.html
>      >
>
>    Do you actually think this is a captured interstellar object?
>
>    What would be its most likely incoming radiant (i.e., where would it be
>    coming from "at infinity")?
>
>    Regards
>    Marshall Eubanks
>
>      > KInd Regards,
>      > Alessandro Odasso >
>      > Links:
>      > ------
>      > [1] https://groups.io/g/mpml/message/35549
>      > [2] https://groups.io/mt/74390462/2048683
>      > [3] https://groups.io/g/mpml/post
>      > [4] https://groups.io/g/mpml/editsub/2048683
>      > [5] https://groups.io/g/mpml/unsub
>
>




seaman@...
 

The heliocentric space-fixed motion of Io loops backwards with each orbit around Jupiter. See JPL Horizons plot on page 7 of:


This may be trivia, but seems meaningful trivia to me. We’d have larger problems if Jupiter disappeared.

Rob Seaman
Catalina Sky Survey


On May 24, 2020, at 1:47 PM, tony873004 <tony@...> wrote:

Some fun meaningless trivia is that the heliocentric orbits of the Galilean Moons are usually hyperbolic. If Jupiter magically disappeared, depending on where the moons were in their orbits, they could do anything from nosedive into the Sun (Io, Europa) or inner solar system, or escape into interstellar space.

On Sun, May 24, 2020 at 8:33 AM Jean Meeus <jmeeus@...> wrote:
When one calculates the HELIOCENTRIC orbit near the time the object is close to Jupiter, one obtains a hyperbolic orbit, that however is meaningless because at that instant the object is attracted more by Jupiter than by the Sun.

Jean Meeus


andrew_j_walker@...
 

On Sun, May 24, 2020 at 04:05 PM, <seaman@...> wrote:
The heliocentric space-fixed motion of Io loops backwards with each orbit around Jupiter. See JPL Horizons plot on page 7 of:
 
 
This may be trivia, but seems meaningful trivia to me. We’d have larger problems if Jupiter disappeared.
 
Rob Seaman
Catalina Sky Survey


On May 24, 2020, at 1:47 PM, tony873004 <tony@...> wrote:

Some fun meaningless trivia is that the heliocentric orbits of the Galilean Moons are usually hyperbolic. If Jupiter magically disappeared, depending on where the moons were in their orbits, they could do anything from nosedive into the Sun (Io, Europa) or inner solar system, or escape into interstellar space.

On Sun, May 24, 2020 at 8:33 AM Jean Meeus <jmeeus@...> wrote:
When one calculates the HELIOCENTRIC orbit near the time the object is close to Jupiter, one obtains a hyperbolic orbit, that however is meaningless because at that instant the object is attracted more by Jupiter than by the Sun.
 
Jean Meeus
https://skyandtelescope.org/astronomy-news/jupiter-has-trapped-a-comet-in-a-bizarre-orbit/?fbclid=IwAR0viU5-tHMEFSDGq6hram8K450Gt2iu5-aXbREBf-0UvqDLejhwsQ6iC54

Has some quotes and graphics from this list.

Andrew