What do you get if you traverse an asteroid with a comet ? An fighting Trojan of form .
Not the funniest of punchlines , but stargazer really have discovered a new sort of asteroid with a comet - like arse that orbits just ahead of Jupiter in a swarm of rock , calledTrojans . 2019 LD2 , as it is known , blurs the boundary between “ dirty snowball”cometsand rockyasteroids , as the object spews dust and gas from its tail - end – like a comet . Although other “ combat-ready asteroids ” with like comet - like propertiesare not unknown , never before has one also been a Jupiter Trojan .
First observed in June 2019 by the University of Hawai’i’sAsteroid Terrestrial - impact Last Alert System(ATLAS ) , 2019 LD2 was earlier thought to be a fainthearted asteroid that shared Jupiter ’s scope around the Sun . Another aspect in July 2019 unveil a comet - similar tush of junk or gas trailing behind the main soundbox , before it dive out of sentiment behind the Sun . When the Trojan asteroid reappeared last month , ATLAS surveys confirmed that almost a year later it still face like a comet .
To attain such demeanor of a Jupiter Trojan is momentous . suppose to have been captured into domain by Jupiter ’s strong gravity billions of year ago , these asteroid should have already been rid of any surface internal-combustion engine that could vaporize and make “ tails ” . Astronomers indicate 2019 LD2 ’s sudden cometary behavior could indicate that it has only recently been captivate by Jupiter from a more distant orbital cavity where ice could exist . Alternatively , it could have of late had a landslide or hit to reveal ice under its layers of protective rock .
Sixty degree ahead and behind Jupiter in its orbital cavity are Lagranian Points , havens of stability where thousands of " Trojan " asteroids congregate .
“ We have trust for tenner that Trojan asteroids should have large amounts of ice beneath their surfaces , but never had any evidence until now , ” Alan Fitzsimmons of Queen ’s University Belfast , Northern Ireland , who helped bring out the asteroid ’s cometary side , said in astatement . “ ATLAS has shown that the predictions of their icy nature may well be right . ”
With thefirst - ever missionto the Trojan Asteroids set up to found next year , researchers are hoping to get a close aspect at the inscrutable behavior of 2019 LD2 . For now , the attention remains on ATLAS to give a view of the eldritch and wonderful world of space rock .
“ Even though the ATLAS system is designed to search for grave asteroids , ATLAS realise other rare phenomena in our solar system and beyond while scanning the sky , ” ATLAS project principal investigator Larry Denneau say in astatement . “ It ’s a real bonus for ATLAS to make these kinds of discoveries . ”
