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Capture of Phobos and Deimos, Paper AAAS - 57725 by Geoffrey Landis
Geert
post Mar 29 2009, 01:23 AM
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see http://arxiv.org/abs/0903.3434

QUOTE
The origin of the Martian moons Deimos and Phobos is controversial. One hypothesis for their origin is that they are captured asteroids, but the mechanism requires an extremely dense martian atmosphere, and the mechanism by which an asteroid in solar orbit could shed sufficient orbital energy to be captured into Mars orbit has not been well elucidated. Since the discovery by the space probe Galileo that the asteroid Ida has a moon "Dactyl", a significant number of asteroids have been discovered to have smaller asteroids in orbit about them. The existence of asteroid moons provides a mechanism for the capture of the Martian moons (and the small moons of the outer planets). When a binary asteroid makes a close approach to a planet, tidal forces can strip the moon from the asteroid. Depending on the phasing, the asteroid can then be captured. Clearly, the same process can be used to explain the origin of any of the small moons in the solar system.


Interesting theory.
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john_s
post Mar 29 2009, 07:30 PM
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A harder question for the capture hypothesis, I think, is why the inclination of the orbits is so low (1.1 and 1.8 degrees for Phobos and Deimos respectively). It's harder to damp inclination than it is to damp eccentricity (Triton, for example, has an inclination of 157 degrees and an eccentricity of zero). Unfortunately this paper doesn't mention inclination damping at all.

John.

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Posts in this topic
- Geert   Capture of Phobos and Deimos   Mar 29 2009, 01:23 AM
- - nprev   Interesting indeed. Hope the full paper is availab...   Mar 29 2009, 01:53 AM
|- - Geert   QUOTE (nprev @ Mar 29 2009, 08:53 AM) Wou...   Mar 29 2009, 02:40 AM
|- - IM4   QUOTE (Geert @ Mar 29 2009, 02:40 AM) In ...   Mar 29 2009, 10:31 AM
- - john_s   A harder question for the capture hypothesis, I th...   Mar 29 2009, 07:30 PM
|- - ugordan   I wondered about inclination, too. Is there any (t...   Mar 29 2009, 07:47 PM
||- - Holder of the Two Leashes   QUOTE (ugordan @ Mar 29 2009, 01:47 PM) I...   May 23 2009, 06:51 PM
|- - sgendreau   QUOTE (john_s @ Mar 29 2009, 11:30 AM) A ...   Oct 25 2009, 08:52 PM
- - nprev   Indeed, John. I was thinking of our own Moon as we...   Mar 29 2009, 07:49 PM
- - ngunn   Does there have to be an intermediate stage where ...   Mar 29 2009, 08:56 PM
- - vk3ukf   Hmm, can I go silly, why not, It was said that ear...   May 23 2009, 09:18 AM
|- - Hungry4info   QUOTE (vk3ukf @ May 23 2009, 04:18 AM) Ma...   May 23 2009, 04:00 PM
||- - Greg Hullender   QUOTE (Hungry4info @ May 23 2009, 09:00 A...   May 23 2009, 05:27 PM
|- - Greg Hullender   QUOTE (vk3ukf @ May 23 2009, 02:18 AM) Hm...   May 23 2009, 05:19 PM
- - Hungry4info   QUOTE ("ugordan")I wondered about inclin...   May 24 2009, 12:11 AM
- - Greg Hullender   It's a tidal effect, and it's caused by th...   May 24 2009, 01:03 AM
- - nprev   What's interesting about Mars wrt tidal dynami...   May 24 2009, 01:19 AM
- - vk3ukf   Could the grooves on Phobos be fracture marks from...   May 24 2009, 11:13 AM
|- - Hungry4info   Full inline quote removed I'm no expert, but ...   May 24 2009, 04:37 PM
- - Shaka   craters or sinkholes?   May 24 2009, 10:29 PM
- - JohnVV   QUOTE Some of the newer images of Phobos show that...   Sep 8 2009, 09:46 PM
- - Floyd   Welcome JohnVV! Really impressive first post....   Sep 8 2009, 10:42 PM
- - JohnVV   QUOTE and those in the lower half run perpendicula...   Oct 1 2009, 05:10 AM
- - remcook   never mind   Dec 11 2009, 11:52 AM


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