It’s raining rocks, get a concrete umbrella

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There’s paper out today, along with a press release about Corot-7b. This is a hot super-earth (4-5.6 Earth masses) in a 20 hour orbit around it’s parent star. It is so close to it’s stellar host that it is tidally locked, meaning one side of it constantly faces the star, the other is in perpetual darkness (like the way we on Earth always see the same face of the Moon). Hence the hot side is about 2300°C, the cold side 220 below frezzing. It was discovered using the transit method by the COROT satellite, an instrument half for planet finding, half for Astroseismology. Previous studies have determined that it is probably a rocky planet like the Earth with a wierd environment, so a team of astronomers based in Washington University, St Louis set about trying to model the atmosphere. The planet’s day side is so hot that rock can be vapourised, so using code developed to study at high temperature vulcanism on Io they simulated how this exotic system would behave. Firstly, the rocky materials would rise, reach a point higher up in the atmosphere where it is cooler, condense and then rain out in the form of pebbles, those minerals with the lowest condensing point falling from the highest height. Secondly the atmosphere would consist of oxygen from the boiled off rocks but also metal vapours like sodium or potassium. Actually sodium has been detected in the atmospheres of other extrasolar planets.

Come to think about it a concrete umbrella would melt, any suggestions for a more effective parasol welcome.

Idea nicked from my former collegue John’s facebook status update.