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 | | From: | Wayne Throop | | Subject: | Re: can a moon sustain life in a solar system? | | Date: | Sat, 22 Jan 2005 22:20:06 GMT |
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 | :: ( I assume you mean "an earth-mass planet orbiting a planet of N^3 :: lunar masses at N times lunar distance, the pair orbiting about :: 1au from the star". Unless I'm not understanding the discussion :: upthread. )
: "Gene Ward Smith" : I wasn't making any assumptions about N, though of course we know it : can be at least as high as 1 and give stable orbits. By orbiting I : meant around the center of mass. How large can N get and still give : us stability?
Ah. Silly me, I was holding the mass constant at N=10.
Well. Fixing that, I get N can be something like 30, corresponding to a mass about that of jupiter, but I don't have much confidence I got it right. It becomes a near thing somewhere around N=8 (where "near thing" is "if tides were 10 percent bigger, it'd fall apart"), so it's skating on thin ice from there on out. Well probably even from further in, I guess.
Thing is, since we're driving mass up proportial to the cube of the distance, gravity of the body keeps up with growth of solar tides for quite a while. In fact, since tides are growing at... hm.
OK, so I'm even *less* confident of my model. I'd be interested to know if N is anywhere *near* being between 8 to 30.
Wayne Throop throopw@sheol.org http://sheol.org/throopw
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