In a first, NASA’s Hubble telescope observes two 'comet-like' asteroids orbiting each other between Mars and Jupiter

Astronomers have observed something rare and unusual in the asteroid belt between Mars and Jupiter. What made the find interesting that the two asteroids circling together were earlier exhibiting all features of a comet – bright coma, long tail – and not an asteroid. This is possibly the first known binary asteroid, classified as a comet, and the discovery is important because the two asteroids orbiting each other make the measurement of their mass possible. “We detected strong indications for the sublimation of water ice due to the increased solar heating — similar to how the tail of a comet is created,” explained team leader Jessica Agarwal of the Max Planck Institute for Solar System Research, Germany. NASA said the combined features of the binary asteroid — wide separation, near-equal component size, high eccentricity orbit, and comet-like activity — also make it unique among the few known binary asteroids that have a wide separation.