COROT planets |
COROT planets |
May 3 2007, 02:20 PM
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Junior Member Group: Members Posts: 22 Joined: 3-January 07 Member No.: 1551 |
http://news.bbc.co.uk/1/hi/sci/tech/6611557.stm
is reporting that Corot has found its first planet. I can't find an arxiv paper about this, or even a press release, but there are many here better at squirreling out data releases than me. 1.3Mj, 1.8Rj so it's a very inflated planet, 1.5-day orbit around a 'star quite similar to the Sun' might account for that. In the Monoceros field (Corot is now pointing at the Scutum/Aquila field). |
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Aug 22 2007, 07:42 PM
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Senior Member Group: Members Posts: 1018 Joined: 29-November 05 From: Seattle, WA, USA Member No.: 590 |
Tidal locking time is an interesting problem.
http://en.wikipedia.org/wiki/Tidal_locking Considering the warning that these figures can be off by a factor of 10, I get the following for putting an Earth with a 12-hour day to start with around some familiar stars: Sol: 365.25 day period, 5.4 billion years to tidally lock. (Ignoring the effect of the moon). Alpha Centauri A: 524-day year, 16 billion years (Earth years) to lock. Tau Ceti: 221-day year, 1.7 billion years Alpha Centauri B: 207-day year, 800 million years Epsilon Eridani: 134-day year, 170 million years Gliese 581: 7.8-day year, 120,000 years. Proxima Centauri: 3.9-hour year, 350 days. The difference between Tau Ceti and Epsilon Eridani surprises me; I hadn't realized there was almost a factor of two luminosity difference, even though the latter is actually slightly more massive. Anyway, even with all the caveats, it seems to be a cinch that any earthlike planet with a period under 100 days will be tidally-locked. (Anyone want to check the math?) --Greg |
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Aug 23 2007, 12:45 PM
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Merciless Robot Group: Admin Posts: 8784 Joined: 8-December 05 From: Los Angeles Member No.: 602 |
Gliese 581: 7.8-day year, 120,000 years. Proxima Centauri: 3.9-hour year, 350 days. So it seems that any true red dwarf exoEarths should blink rapidly enough for detection using mass sampling...sounds like a seed for a mission proposal, here, if the observable (key point; they're so damn faint that they'd have to be fairly nearby) number of dwarves is large enough to make it worthwhile. -------------------- A few will take this knowledge and use this power of a dream realized as a force for change, an impetus for further discovery to make less ancient dreams real.
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