Planet Found With Comet-like Tail
Comet-like planets could be fairly common, expert says.
(Related: "Odd Star Sheds Comet-like Tail.")
About 153 light-years from Earth, planet HD 209458b hugs its star so tightly that the planet's atmosphere is likely a scorching 2,000 degrees Fahrenheit (1,093 degrees Celsius) an a year passes in just 3.5 days—making Mercury's 88-day orbit seem downright leisurely.
That tight orbit also means this gas giant—meaning it's made primarily of gas—is subjected to blistering forces from its host star, which scientists say are the cause of HD 209458b's comet-like tail.
"This planet is getting blasted by the star and that's blowing the atmosphere off," said astronomer Cynthia Froning of the University of Colorado, who was involved in the study of the comet-like planet.
(Also see "Star 'Eating' Superhot Planet's Atmosphere.")