Wednesday, September 16, 2009

First Rocky Exoplanet Discovered

According to the Telegraph (UK), a planet first discovered in February has been determined to have a mass and volume (giving a resulting density) indicating that it has a rocky composition! All other planets discovered so far (373 according to NASA/JPL) are either gaseous, or orbit pulsars. I haven't looked through the database, but I presume there are planets for which densities have not been determined. From what I know, I think the planet would have to transit between its host star and us for astronomers to determine its diameter.

Corot-7b, as the planet has been designated, orbits its primary star at a distance of only 2.5 million km (Earth orbits at about 150 million km), so it's much too hot to host life. The article implies that it is tidally locked, with one side facing its star all the time; bright side temperatures are estimated to be 2000 C, dark side temps at -200 C. However, the mere fact of discovering one terrestrial planet means there are others, some of which are likely to be in the Goldilocks zone...

Amazing. Awesome. Words fail.

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