NASA's Wide-field Infrared Survey Explorer (WISE) has finally determined centaurs, the small celestial bodies orbiting the sun between Jupiter and Neptune, to be comets.
The true identity of centaurs has remained a mystery to scientists for a long time now. They have continuously speculated if the small celestial bodies orbiting the sun between Jupiter and Neptune are comets or asteroids. They remained perplexed about whether centaurs are asteroids flung out from the inner solar system or comets traveling in toward the sun from afar.
However, in a recent discovery, NASA's Wide-field Infrared Survey Explorer (WISE) finally determined that most centaurs are actually comets.
"Just like the mythical creatures, the centaur objects seem to have a double life," said James Bauer of NASA's Jet Propulsion Laboratory in Pasadena, Calif in a press release. He is also the lead author of a similar paper published online July 22 in the Astrophysical Journal. "Our data point to a cometary origin for most of the objects, suggesting they are coming from deeper out in the solar system."
By "cometary origin", Bauer means that the object is likely to be made of the same material as a comet. It may have been an active comet in the past and may be active again in the future.
The discovery was made after NEOWISE, the asteroid-hunting portion of the WISE mission, gathered infrared images of 52 centaurs, of which fifteen were new discoveries. Centaurs are known to orbit in an unstable belt. The gravity from other large planets generally either push them closer to the sun or farther away from their current location.
"Comets have a dark, soot-like coating on their icy surfaces, making them darker than most asteroids," said the study's co-author, Tommy Grav of the Planetary Science Institute in Tucson, Ariz. "Comet surfaces tend to be more like charcoal, while asteroids are usually shinier like the moon."
Findings from the observations of the infrared images revealed that two-thirds of centaurs are comets. However they remain uncertain on the remaining one third centaurs and their nature.
The study was published online in the journal IOP Science.
