NASA | Colliding Comets Hint at Unseen Exoplanet

An international team of astronomers exploring the disk of gas and dust the bright star Beta Pictoris have uncovered a compact cloud of poisonous gas formed by ongoing rapid-fire collisions among a swarm of icy, comet-like bodies. The researchers suggest the comet swarm may be frozen debris trapped and concentrated by the gravity of an as-yet-unseen planet. Using the Atacama Large Millimeter/submillimeter Array (ALMA) in Chile, astronomers mapped millimeter-wavelength light from dust and carbon monoxide (CO) molecules in a disk surrounding the star. Located about 63 light-years away and only 20 million years old, Beta Pictoris hosts one of the closest, brightest and youngest debris disks known, making it an ideal laboratory for studying the early development of planetary systems. The ALMA images reveal a vast belt of carbon monoxide located at the fringes of the system. Much of the gas is concentrated in a single clump located about 8 billion miles (13 billion kilometers) from the star, or nearly three times the distance between the planet Neptune and the sun.