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The asteroid in question, named (101429) 1998 VF31, is part of a group of Trojan asteroids that share the orbit of Mars.
Trojans are celestial bodies that fall into gravitationally balanced regions of space in proximity to other planets, located 60 degrees in front of and behind the planet.
Most of the Trojan asteroids we know share Jupiter’s orbit, but other planets do too, including Mars and Earth.
What makes (101429) 1998 VF31 (hereafter “101429”) interesting is that among the Red Planet’s queuing Trojans (those that follow Mars as it orbits the Sun), 101429 appears to be unique.
The rest of the group, called L5 Martian Trojans, belongs to what is known as the Eureka family, consisting of 5261 Eureka – the first Mars Trojan discovered – and a bunch of small fragments believed to have broken off from the parent space rock.
101429 is different, however, and in a new study by astronomers from the Armagh Observatory and Planetarium (AOP) in Northern Ireland, researchers wanted to investigate why.
Using a spectrograph called the X-SHOOTER on the 8-m Very Large Telescope (VLT) of the European Southern Observatory in Chile, the team examined how sunlight reflects off 101429 and its L5 relatives in the Eureka family. Only, it appears that 101429 and the Eureka clan are not related after all, with analysis revealing that 101429 shows a spectral match for a satellite much closer to home.
“The spectrum of this particular asteroid seems to be almost a wake-up call for parts of the Moon where exposed bedrock is present such as the interior of craters and mountains,” explains AOP astrochemist Galin Borisov.
While we can’t yet be sure why, the researchers say it’s plausible that the origins of this Martian Trojan started somewhere far away from the Red Planet, with 101429 representing a “relic fragment of the original solid crust of the Moon.”
If that’s true, how did the Moon’s lost twin end up as a Mars-linked Trojan?
“The early solar system was very different from the place we see today,” explains the study’s lead author, astronomer AOP Apostolos Christou.
“The space between the newly formed planets was full of debris and collisions were the order of the day. Large asteroids [planetesimals] they constantly hit the Moon and other planets. A fragment of such a collision could have reached the orbit of Mars when the planet was still forming and was trapped in its clouds of Troy. “
It’s a captivating idea, but researchers say it’s not the only explanation for 101429’s past. It is also possible, and perhaps more likely, that the trojan instead represents a fragment of Mars chipped by a similar type of accident it has hit the Red Planet; or it could be just a common asteroid that, through the alteration of solar radiation, has come to resemble the Moon.
Further observations with even more powerful spectrographs may be able to shed more light on this issue of space kinship, as could a future visit by a spacecraft, the team says, “which could, en route to the Trojans, obtain specters on Mars or the Moon for direct comparison with asteroid data “.
The results are reported in Icarus.
This article was originally published by ScienceAlert. Read the original article Here.
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