Artist’s View of Extrasolar Planet WASP-12b

Pitch-Black Exoplanet is Super-Hot

This illustration shows one of the darkest known exoplanets — an alien world as black as fresh asphalt — orbiting a star like our Sun. The day side of the planet, called WASP-12b, eats light rather than reflects it into space. The exoplanet, which is twice the size of Jupiter, has the unique capability to trap at least 94 percent of the visible starlight falling into its atmosphere. The temperature of the atmosphere is a seething 4,600 degrees Fahrenheit, which is as hot as a small star.

The day side hordes all the visible light because it always faces its star. The planet orbits so close to its host that it has fixed day and night sides. WASP-12b is about 2 million miles away from its star and completes an orbit once a day. The night side is much cooler, with temperatures roughly 2,200 degrees Fahrenheit, which allows water vapor and clouds to form. A swirl of material from the planet’s super-heated atmosphere is spilling onto its star.

This oddball exoplanet is one of a class of so-called "hot Jupiters" that orbit very close to their host star and are heated to enormous temperatures.