Astronomers spot a strange, first-of-its-kind asteroid near Jupiter - Engadget

Researchers using the University of Hawaii’s Asteroid Terrestrial-impact Last Alert System (ATLAS) have found (via Gizmodo) a Trojan asteroid, 2019 LD2, that not only follows an odd orbit ahead of Jupiter but also sports an icy tail — it’s a unique “crossover” between asteroid and comet.

It only appears to have been active for less than a year, too, which is unusual when Jupiter Trojans are often billions of years old and should have lost their ice a long time ago.

More data will be needed to determine just what led to this one-of-a-kind finding, but the university’s Institute for Astronomy suggested that Jupiter might have recently captured the asteroid from a distant (and thus colder) orbit, or that a collision with another space rock might have exposed ice that was previously ‘safe’ from the Sun’s heat.