THE CARBON MONOXIDE COMET: Astronomers are marveling at the wild blue color and even wilder dynamics of Comet PanSTARRS (C/2016 R2), now approaching the sun beyond the orbit of Mars. Every day, it seems, another cloud of dusty gas billows down the comet’s tail as gaseous jets swivel around the comet’s core. This is what the comet looked like on Jan. 10th:
Amateur astronomer Gerald Rhemann took the picture from his private observatory in Farm Tivoli, Namibia. “This is a 56 minute guided exposure through a 12-inch telescope,” he explains.
The comet’s extraordinary behavior can be traced to one key ingredient: carbon monoxide (CO). The comet’s core is spewing 4.7 x 1028 CO molecules into space every second, according to recent measurements at the Arizona Radio Observatory’s 10-m Submillimeter Telescope. This accounts for the comet’s lovely color (because ionized CO glows blue) and its hyperactivity. Carbon monoxide is extremely volatile. CO can sublimate (change suddenly from solid to gas) at temperatures as low as -248 C (25 K). Only a little bit of sunlight is required to turn deposits of frozen CO into wild jets and billowing clouds.