Centaurs Are Not Like Comets After All

Using the Gemini North telescope to look at a selection of centaurs found in PANSTARRS-1 data, scientists find 13 that do not have comet-like tails.

IMAGE: Centaurs look like nothing more than moving dots in the sky when viewed from Earth. These images are inverted — bright objects appear black — to make it easier to see faint targets. CREDIT: Lilly et al., 2021

Back here in our solar system, researchers here at the Planetary Science Institute have had a bit of a breakthrough when it comes to understanding one of the more mythical beasts we’ve discovered — centaurs.

Centaurs are a strange combination of asteroid and comet, big lumps of rock and ice out between the orbits of Jupiter and Neptune that occasionally put on a show by growing comas. They’re a curious creature, and to that end, a team of researchers got time on the Gemini North telescope in Hawaii to look at a selection of centaurs found in PANSTARRS-1 survey data.

Here’s the funny bit — they weren’t looking for inactive centaurs; they were looking for those comet-like tails. And found exactly none of the 13 bodies they were able to observe. But sometimes, not finding what you are looking for can give you insight into the inner workings of a system. In this case, by finding all these inactive centaurs, the team found a potential reason for just how the active ones begin giving off gas and dust.