Comments on: Orbits and Origins of Two New Moons of Pluto http://www.anthonares.net/2006/02/orbits-and-origins-of-two-new-moons-of-pluto.html Chronicling and Commenting on Human Progress Thu, 29 Jul 2010 12:19:30 +0000 http://wordpress.org/?v=2.2 By: christine http://www.anthonares.net/2006/02/orbits-and-origins-of-two-new-moons-of-pluto.html#comment-36017 christine Sun, 21 Dec 2008 13:13:30 +0000 http://www.anthonares.net/2006/02/orbits-and-origins-of-two-new-moons-of-pluto.html#comment-36017 Is there no picture that is closely captured the planet pluto? Is there no picture that is closely captured the planet pluto?

]]> By: Anthony Kendall http://www.anthonares.net/2006/02/orbits-and-origins-of-two-new-moons-of-pluto.html#comment-229 Anthony Kendall Sun, 05 Mar 2006 00:13:23 +0000 http://www.anthonares.net/2006/02/orbits-and-origins-of-two-new-moons-of-pluto.html#comment-229 The resonances can be of a few types: 1) In the case of Mercury, the resonance is one between the orbital period and the rotational period. This results, despite the near-circular orbit, from tidal distortions and may eventually lead to complete tidal locking. 2) For circular orbits of satellites that are large compared to their host planet, the actual point of rotation is known as the barycenter of the orbit, and for the case of Pluto and Charon is far enough away from Pluto so as to make Pluto noticeably orbit the barycenter. In this case, with two planets orbiting their barycenter the rotation can easily reach resonance. 3) In the case of P1 and P2, the orbits are resonant probably because they were formed initially from the same impact that formed Charon, or so the authors speculate. So in this case I think the resonance was there from the very beginning. Also, the orbits were initially non-circular very likely, but because P1 and P2 were so close to Pluto/Charon their apoapsis quickly decayed. Then, as the Pluto/Charon system evolved, the transfer of angular momentum allowed P1 and P2 to move further out. I hope this addresses your question. If not, perhaps you could clarify it for me a bit. The resonances can be of a few types:
1) In the case of Mercury, the resonance is one between the orbital period and the rotational period. This results, despite the near-circular orbit, from tidal distortions and may eventually lead to complete tidal locking.
2) For circular orbits of satellites that are large compared to their host planet, the actual point of rotation is known as the barycenter of the orbit, and for the case of Pluto and Charon is far enough away from Pluto so as to make Pluto noticeably orbit the barycenter. In this case, with two planets orbiting their barycenter the rotation can easily reach resonance.
3) In the case of P1 and P2, the orbits are resonant probably because they were formed initially from the same impact that formed Charon, or so the authors speculate. So in this case I think the resonance was there from the very beginning. Also, the orbits were initially non-circular very likely, but because P1 and P2 were so close to Pluto/Charon their apoapsis quickly decayed. Then, as the Pluto/Charon system evolved, the transfer of angular momentum allowed P1 and P2 to move further out.

I hope this addresses your question. If not, perhaps you could clarify it for me a bit.

]]> By: Toby Kelsey http://www.anthonares.net/2006/02/orbits-and-origins-of-two-new-moons-of-pluto.html#comment-228 Toby Kelsey Sat, 04 Mar 2006 23:05:04 +0000 http://www.anthonares.net/2006/02/orbits-and-origins-of-two-new-moons-of-pluto.html#comment-228 While your explanation of tidal locking makes sense, I don't understand the mechanism which could create orbital resonance for satellites in circular orbits. For elliptical orbits interactions at periapsis can have an effect, but for circular orbits there would seem to have to be an asymmetric interaction with the fixed stars to cause satellite locations to be preferentially synchronized in a particular (fixed) direction. Perhaps the synchronization is in the Sun-radial direction? Toby While your explanation of tidal locking makes sense, I don’t understand the mechanism
which could create orbital resonance for satellites in circular orbits. For elliptical orbits
interactions at periapsis can have an effect, but for circular orbits there would seem to
have to be an asymmetric interaction with the fixed stars to cause satellite locations
to be preferentially synchronized in a particular (fixed) direction. Perhaps the
synchronization is in the Sun-radial direction?

Toby

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