Astronomers recently observed a type of object in space unlike anything we’ve come across before. 288P is a binary asteroid – or two asteroids orbiting one other – that has features similar to a comet, like a long tail and bright coma, or cloud of dust and gas surrounding a comet’s nucleus. It is the first binary asteroid we’ve ever found that can also be classified as a comet.
Scientists learned of 288P’s existence in 2011, but they weren’t able to really scrutinize the binary asteroid – it was too far away – until recently when it came a little closer to Earth. Using the NASA/ESA Hubble Space Telescope, a group of scientists led by Jessica Agarwal at the Max Planck Institute for Solar System Research in Germany were able to get a better look at the strange system.
288P is a main-belt comet as it’s located in the asteroid belt between Mars and Jupiter. Each of the two pieces that make up 288P are about 0.6 miles in diameter, and the research institute said they are unusually far apart: they’re orbiting one another at a distance of around 62 miles. The astronomers also observed ongoing activity in 288P. Agarwal said, “We detected strong indications of the sublimation of water ice due to the increased solar heating – similar to how the tail of a comet is created.”
288P has probably been a binary system for just around 5,000 years. And according to Hubble’s website, we’re not likely to find any more objects like 288P for a long time, since finding the binary main-belt comet “included a lot of luck.”
The journal Nature published the research online earlier this week. Agarwal was joined by four other researchers from institutions in the United States.