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The last week has had a number of very interesting exo-planet discoveries (particularly Gliese 581 c and the first Corot planet). Another one that came out maybe two days ago or so is the discovery of a transiting super-massive planet (8 times the mass of jupiter) by the HAT network. You can find a short discussion and a link to the paper here: http://oklo.org/?p=208 as well as a discussion on some of the very interesting preliminary modeling of this planet's weather here: http://oklo.org/?p=210 . <br /><br />This planet is actually very interesting in a number of ways. First of all, it's the first transiting planet that's substantially larger than jupiter, although many of these had been known from the radial velocity surveys. Finding a transiting example is very interesting because that gives the density and opens up all the fun follow-up. While the planet has 8 times Jupiter's mass, it's radius is only slightly larger than Jupiter which gives it a density of about 6 grams/cc. This is actually quite reassuring because it's very close to what was predicted for planets this big (jupiter, brown dwarfs and small m-dwarf stars are thought to all have roughly the same diameter) - and in fact theorists were much more confident about the predicted mass/radius relation for these very big planets than they are for jupiter size and smaller planets. <br /><br />The other really interesting thing about this planet is that it has such a high orbital eccentricity, so its insolation changes by something like a factor of 9. That means this planet will almost certainly have some incredible weather - many aspects of which may be detectable with Spitzer. <div class="Discussion_UserSignature"> </div>