Mysterious comets hiding in the asteroid belt

As in other comets, the main belt comet’s ices evaporate and go into a coma as it whizzes away from the sun. But, oddly enough, it rotates in the asteroid belt, a graveyard debris that did not coalesce into the planets.

It was the first major belt comet Discovered in 1996“But you can always interpret something as whimsical,” said Dr. Snodgrass, suggesting that the belt could have captured an intervening comet. However, eight more have since been discovered. About 20 other belt-related objects have been seen falling – possibly due to periodic evaporation of comet-like ice, a wild spin or more recent asteroid impacts They are considered candidates to be guilty.

The researchers from the study, hoping to discover more mainbelt defectors, found only one new candidate: 2001 NL19.

“It’s the only thing that seems to have a little something in it,” said Ms. Verelich, describing the faint, tail-like body feature that turns away from the sun. It could have been born from the evaporation of ice, making the body comet. More observations will be necessary as it approaches the Sun again, when a coma or tail is most likely to appear.

Regardless of how 2001 NL19 is classified, the number of confirmed main belt comets indicates that “these things are native to the asteroid belt,” said Dr. Snodgrass. Their genesis remains a mystery, although some ideas have been proposed.

Main belt comets, like their traditional distant counterparts, may have formed far from the Sun during the solar system’s chaotic early days, but rather than staying far away, they were flung away by the gravity of other bodies and embedded in what is now an asteroid. Belt. After billions of years, any remaining primordial ice will be buried beneath their rocky surfaces. If they hit another asteroid, some of this The ice will be drilledAnd expose him to the scorching starlight.

Doubts aside, one thing is clear: The existence of these asteroid-comet screwballs complicates the desire to put natural phenomena into neat little boxes.

“I always say: everything is a comet,” said Kacper Wierzchos, an astronomer at the University of Arizona’s Lunar and Planetary Laboratory who was not involved in the study. “If I bring my couch close enough to the sun, it will start to melt and go into a coma.”