Keck Observatory announces discovery of super-Earth HD156668b, just 4.15 times more massive than Earth
Friday, January 08, 2010
Here's a nice surprise from today - the announcement of the discovery of another super-Earth, the second lightest planet we know of. The planet is called HD156668b and thus orbits the star HD156668, but there doesn't seem to be any information about the star itself online. The planet has an orbital period of just 4.6 days though which is extremely close, and even if the star is a red dwarf it would still be located too far in to be placed in the habitability zone. Gliese 581 e is one other example we have of a super-Earth located that close to its star. Gliese 581 c is in the habitability zone (though apparently would still be too hot) with an orbital period of 12 days, and Gliese 581 d with an orbital period of 66 days would apparently be too far away but a large enough greenhouse effect would make it sufficient to support life (as we know it). You can see that even a planet located well within the orbit of Mercury is still too far away to support an earthlike temperature without it:
I'll update the post when some more information on HD156668 itself is found.
Edit: hm, assuming this link is correct it looks like this star is spectral type K2, or an orange giant.