COROT planets Options

[Tom Womack]

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).

[Greg Hullender]

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

[belleraphon1]

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.
--Greg

So what if it is tidally locked?

http://www.liebertonline.com/doi/abs/10.1089/ast.2006.0124

http://www.astrobio.net/news/article1694.html

Craig

[stevesliva]

So what if it is tidally locked?

Iiiiinteresting. I wonder what the climate models predict for temperature maps on the sun-facing side?

I also find it interesting that the earth would be tidally locked in a mere 5 billion years sans luna.

[belleraphon1]

Iiiiinteresting. I wonder what the climate models predict for temperature maps on the sun-facing side?

I also find it interesting that the earth would be tidally locked in a mere 5 billion years sans luna.

"Simulations of the Atmospheres of Synchronously Rotating Terrestrial
Planets Orbiting M Dwarfs: Conditions for Atmospheric Collapse and
the Implications for Habitability"
http://www.seismo.unr.edu/ftp/pub/gillett/joshi.pdf

Also, ANY terrestrial planet around any star will probably lose the internal heat needed to keep plate techtonics going after 10 billion years or so. When that ends, the cycles that reprocess the geochemical needs of a biosphere will grind to a halt.

A lot of interesting studies going on ........................ what COROT and KEPLER may give us is a stat on
how prevalent the above fates are.

Craig

[tty]

Also, ANY terrestrial planet around any star will probably lose the internal heat needed to keep plate techtonics going after 10 billion years or so. When that ends, the cycles that reprocess the geochemical needs of a biosphere will grind to a halt.

That would depend on the amount of uranium present to begin with. Also geochemical cycling would not stop completely even in the absence of tectonics. For example glacial erosion can be very powerful and impact cratering would have some effect too. I would expect that some kind of low-nutrient, low-energy biosphere would persist rather like what we have in Australia (where there has been practically no tectonics over most of the continent for hundreds of million years).