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Could newly-discovered 2020 XL5 be an Earth Trojan?


tony873004
 

2020 XL5 's nominal trajectory from JPL Horizons shows it librating about Earth's L4 point.
http://orbitsimulator.com/BA/2020_XL5_c.gif

100/100 clones generated with FindOrb are doing the same.
http://orbitsimulator.com/BA/2020_XL5.JPG


Sam Deen
 

I'll search for some precoveries to figure out for sure. I will say now: It can't be an extremely stable Trojan. The eccentricity cutoff for most stable Jupiter Trojans seems to be 0.3, with a decent handful above 0.2. This object's eccentricity is nearly 0.39 and I expect Earth's threshold is even lower!

~Sam

On Tuesday, January 26, 2021, 6:18:55 PM PST, tony873004 <tony@...> wrote:


2020 XL5 's nominal trajectory from JPL Horizons shows it librating about Earth's L4 point.
http://orbitsimulator.com/BA/2020_XL5_c.gif

100/100 clones generated with FindOrb are doing the same.
http://orbitsimulator.com/BA/2020_XL5.JPG


andrew_j_walker@...
 

It also has a MOID of 0.0273 au with Venus so over time it will become less stable.

The JPL site has a number of encounters with Earth and Venus listed, but the distances
mostly have a large error. A longer arc will improve this a lot!

Andrew


On Tue, Jan 26, 2021 at 06:23 PM, Sam Deen wrote:
 
I'll search for some precoveries to figure out for sure. I will say now: It can't be an extremely stable Trojan. The eccentricity cutoff for most stable Jupiter Trojans seems to be 0.3, with a decent handful above 0.2. This object's eccentricity is nearly 0.39 and I expect Earth's threshold is even lower!
 
~Sam
 
On Tuesday, January 26, 2021, 6:18:55 PM PST, tony873004 <tony@...> wrote:
 
 
2020 XL5 's nominal trajectory from JPL Horizons shows it librating about Earth's L4 point.
http://orbitsimulator.com/BA/2020_XL5_c.gif

100/100 clones generated with FindOrb are doing the same.
http://orbitsimulator.com/BA/2020_XL5.JPG


Aldo Vitagliano
 

Hi all,

I can confirm that 2000 XL5 is presently a moderately stable Earth Trojan (I mean stable on a time scale of 2-4 millennia).
I have downloaded the nominal elements and their covariance matrix from the Neodys site, thereby generating 200 clones of the body.
All the 200 clones, integrated up to AD 4500, although becoming spread over an orbital arc of more than 120 degrees, keep librating around the L4 point.
The first clone jumps over the L3 point around year 4500, and by year 6000 many of them have done of jump and a few of them are librating around the L5 point.

Regards
Aldo Vitagliano

www.solexorb.it




tony873004 <tony@gravitysimulator.com> ha scritto:

2020 XL5 's nominal trajectory from JPL Horizons shows it librating about
Earth's L4 point.
http://orbitsimulator.com/BA/2020_XL5_c.gif

100/100 clones generated with FindOrb are doing the same.
http://orbitsimulator.com/BA/2020_XL5.JPG





Wiggins Patrick
 

Pardon the pretty much off topic reply but you can tell I’m old since “XL5” reminded me of this from when I was a wee one:
https://en.wikipedia.org/wiki/Fireball_XL5

patrick :)
718

On 26 Jan 2021, at 19:18, tony873004 <tony@gravitysimulator.com> wrote:

2020 XL5 's nominal trajectory from JPL Horizons shows it librating about Earth's L4 point.
http://orbitsimulator.com/BA/2020_XL5_c.gif

100/100 clones generated with FindOrb are doing the same.
http://orbitsimulator.com/BA/2020_XL5.JPG


tony873004
 

Here's an animation showing why Venus can not destabilize 2020 XL5's Trojan configuration at the moment.
http://orbitsimulator.com/BA/2020_XL5_Venus_Plane.gif  
The simulation uses JPL Horizons nominal position and velocity vectors as a starting point.
The bright yellow is where the asteroid is above the plane of Venus' orbit, and the dark yellow is below, with the transitions showing the ascending and descending nodes.
When the asteroid is at Venus' distance from the Sun, it currently passes too high above Venus, or too low. But as the nodes precess over the centuries, and get close to Venus (lowering its MOID with Venus), Venus has a large influence on the asteroid's orbit, changing the shape of trojan orbit, ultimately sending it  over the L3.



On Thu, Jan 28, 2021 at 11:17 PM Wiggins Patrick <4099wiggins@...> wrote:
Pardon the pretty much off topic reply but you can tell I’m old since “XL5” reminded me of this from when I was a wee one:
https://en.wikipedia.org/wiki/Fireball_XL5

patrick  :)
718

> On 26 Jan 2021, at 19:18, tony873004 <tony@...> wrote:
>
> 2020 XL5 's nominal trajectory from JPL Horizons shows it librating about Earth's L4 point.
> http://orbitsimulator.com/BA/2020_XL5_c.gif
>
> 100/100 clones generated with FindOrb are doing the same.
> http://orbitsimulator.com/BA/2020_XL5.JPG
>