The exoplanet Corot-7b has earned a reputation as one of the most interesting planets yet spotted outside our solar system, mostly because of its similarities to Earth: Astronomers have determined that it’s rocky, like Earth, and it’s only about five times more massive than our home planet. But the dissimilarities are just as fascinating. In the latest twist, a new study has suggested that storm fronts on Corot-7b may bring a rain of pebbles.
The alien planet is extraordinarily close to its parent star, and researchers think that it’s tidally locked so that one hemisphere always faces the star’s blasting heat. On that side, temperatures are thought to reach about 4,220 degrees Fahrenheit—hot enough to vaporize rock. So unlike the much cooler Earth, COROT-7b has no volatile gases (carbon dioxide, water vapor, nitrogen) in its atmosphere. Instead it’s atmosphere consists of what might be called vaporized rock. “The only atmosphere this object has is produced from vapor arising from hot molten silicates in a lava lake or lava ocean” [SPACE.com], says study coauthor Bruce Fegley Jr.
Using computer models, the researchers set out to determine how this strange atmosphere would behave. The results, which will be published in The Astrophysical Journal, suggest that during storms, pebbles may condense out of the atmosphere. “As you go higher the atmosphere gets cooler and eventually you get saturated with different types of ‘rock’ the way you get saturated with water in the atmosphere of Earth,” Fegley explained. “But instead of a water cloud forming and then raining water droplets, you get a ‘rock cloud’ forming and it starts raining out little pebbles of different types of rock” [SPACE.com].
80beats: Rock Solid Evidence of a Rocky, Earth-like Exoplanet
80beats: Small, Rocky Exoplanet Is the Most Earth-Like World Ever Seen
DISCOVER: How Long Until We Find a Second Earth?
Image: European Southern Observatory. An artist’s impression of Corot 7b.