Second Earth Trojan Asteroid Discovered 

Posted: February 5, 2021 by oldbrew in Astronomy, solar system dynamics
Tags: ,

Lagrange points in the Sun–Earth system (not to scale). A small object at L4 or L5 will hold its relative position [Credit: Xander89 @ Wikipedia]

More about Lagrange points here.
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A recently discovered asteroid appears to be an Earth Trojan, orbiting a gravitationally stable area with only one other known occupant, says Sky & Telescope.

Trojans are asteroids gravitationally locked to stable Lagrange points either 60° ahead (L4) or behind (L5) the planets in their orbits around the Sun. 2020 XL5 was found around the L4 point.

Massive Jupiter has more than 9,000 Trojans.

In theory, Trojan orbits would be stable around every planet except Saturn, where Jupiter’s gravity pulls them away.

So far, Trojans have been found sharing orbits — at least temporarily — with Neptune, Uranus, Mars, Venus, and Earth.

Earth Trojans are hard to find because during most of their orbits, they appear close to the Sun in the sky.

Not only that, but the gravitational resonance does not hold them in lockstep at 60° ahead and behind of the Earth, explains Dunn.

Instead, the objects trace paths around the L4 and L5 points, which are themselves moving as Earth orbits the Sun.

NASA’s Wide-field Infrared Survey Explorer spacecraft spotted the first Earth Trojan, 2010 TK7, also locked to the L4 point, in October 2010 when it scanned the infrared sky 90° from the Sun. Two other observers recovered it a few months later with the Canada-France-Hawaii Telescope. It’s slightly smaller than 2020 XL5.

The orbits of our two Trojans are best visualized along with that of Earth’s and, in the case of 2020 XL5, the orbits of all the inner planets.

When viewed relative to Earth, 2010 TK7 drifts between a spot close to Earth to the L3 point on the other side of the Sun from Earth, but it doesn’t pass through the L4 point.

The orbit of 2020 XL5 ranges more widely, drifting inward to inside Venus’s orbit and outward almost to Mars [as shown here].

Full article here.
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Animation showing the Lagrange points (the triangles are equilateral).

  1. oldbrew says:

    NEODYS says its perihelion distance from the Sun is 0.6133, so the ratio of that to Earth’s perihelion distance is close to the golden ratio (~0.618:1).

    Maybe that has something to do with it ‘orbiting a gravitationally stable area’.

  2. JB says:

    I think you’re on to something there, OB

  3. Paul Vaughan says:

    LAG-rains Point We[at]Rust Not $0[]We11

    Bi-collar communication is hybridized for read white (1/5) & blue (4/5) collar together (on the Pareto Principle).

    Simple: green like play yen banjo$.

    25757.05496809 = beat(0.615197263396975,0.61518257)
    25763.987503107 = beat(1.00001743371442,0.99997862)

    Earth & Venus are coupled and Saturn has a special[?wha?]weigh with a home “more simmm… pull man“.

    25760.5207691867 = harmean(25763.987503107,25757.05496809)
    25759.505729618 = (1+MOD(29.42351935,1)+1+1)/(1/23094.6280196893+MOD(29.42351935,1)/36133.4834429379+1/26114.2236547808+1/25259.6956047047)
    0.003940446604 = % error

    Sol ID Explore a Tory Con Tent

    IT‘s B-Ace Bo11inger washUNtune44 ’22 Ru$tie! re[a]d$sox play yen left fields$green monde$star:

    “The lovesh!hack:AP11aceSWear ‘‘We’ can ‘get TO’ gather….loves hack ⌊Bei,AB⌋ ON the ⌊F[u]11 Or[We’11] Be!,AB⌋ “ — the Bee[φ]ive t[r]ee [ch]oo$e

    Goa11 F(UN) what’s par 44 the course 22 UN IT. This$aint$shyenBaceBo11MITa11iz. Fine nun$y(e/11) “in equal ITee”.

    D-air west turn math ‘education’ (what they call IT) to root ‘Cause’ of D-evil grip link UN PR Joe Act. He ignore number 163. And that is why we have to prove peacefully that “in God we trust”. We have to do it peacefully. Thus freeze peach.

  4. Jim says:

    I was thinking along another line. Does that mean, that earth must be declared a minor planet, the same as pluto, since we have not cleared our orbital path?

  5. oldbrew says:

    Jim says: February 6, 2021 — Does that mean, that earth must be declared a minor planet, the same as pluto, since we have not cleared our orbital path?
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    No. Jupiter has thousands of trojans…

    (white dots are the main belt asteroids)

  6. Jim says:

    So, it failed also, minor planet?