Temporary companion: Astronomers find a new Trojan asteroid near Mars

A team of Spanish astronomers has confirmed that asteroid 2023 FW14 is “accompanying” the Red Planet on its journey around the Sun. Thus, the total number of known Trojan asteroids on Mars has increased to 17.

Trojan asteroid near Mars in the artist’s impression. Source: SMM, IAC

2023 FW14 was discovered last year. It is a relatively small asteroid — its diameter is estimated at 320 meters. 2023 FW14 is located in the vicinity of the Lagrange point (L4) of the Sun–Mars system. Thus, it is in the same orbit as Mars, ahead of it in its movement. Such objects are called Trojan asteroids.

Observations made with the GTC telescope have shown that the spectrum of 2023 FW14 differs from most other Trojans of the Red Planet. Like its neighbor at point L4 (object 1999 UJ7), it is a so-called primitive type asteroid. This is how they differ from the 15 asteroids located at point L5, which are rocky asteroids rich in silicates.

Another important difference is the orbit. 16 previously known Martian Trojans are likely to accompany the planet from the epoch of its formation, and their orbits are stable in the long term. But this cannot be said about 2023 FW14. Calculations showed that it moved to the vicinity of the L4 point only a million years ago and would leave it in ten million years. 

According to the researchers, they have two main versions of the origin of 2023 FW14. It could either be a fragment of 1999 UJ7, or it could have been captured from a population of near-Earth asteroids that cross the orbit of Mars. 

At the moment, astronomers have managed to find Trojan asteroids on all planets of the Solar System, except Mercury and Saturn. Jupiter has the largest population of such objects. They will be the object of study of the Lucy mission, which will fly at least eight Jupiter Trojans between 2027 and 2033.

According to https://phys.org

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