What do you call an asteroid when it’s not an asteroid? A comet — that’s also an asteroid.
Astronomers have determined a newly discovered celestial object has a frozen core like a comet, but with an orbit more in line with an asteroid.
The Asteroid Terrestrial-Impact Last Alert System (ATLAS) survey discovered asteroid (248370) 2005 QN137 was active on July 7, 2021.
‘It fits the physical definitions of a comet, in that it is likely icy and is ejecting dust into space, even though it also has the orbit of an asteroid,’ Henry Hsieh, a researcher with the Planetary Science Institute, said in a presentation on Monday.
‘This duality and blurring of the boundary between what were previously thought to be two completely separate types of objects — asteroids and comets — is a key part of what makes these objects so interesting.’
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Astronomers believe asteroid 248370 is icy and expelling dust like a comet, but has an orbit more in line with an asteroid. ‘This duality and blurring of the boundary between what were previously thought to be two completely separate types of objects … is a key part of what makes these objects so interesting,’ said Henry Hsieh, a researcher with the Planetary Science Institute
Out of more than half a million known main-belt asteroids, 248370 is one of only eight confirmed to have been active more than once.
‘This behavior strongly indicates that its activity is due to the sublimation of icy material,’ said Hsieh.
That ‘icy material’ suggests it’s also a comet.
A main-belt comet, to be precise—one of only about 20 celestial objects suspected or confirmed to be, Hsieh said, ‘including some that have only been observed to be active once so far.’
The hybrid, which Hsieh calls a ‘main-belt comet,’ was discovered hidden among the asteroids in the inner solar system.
