[meteorite-list] Catch A Comet?

From: Richard Kowalski <damoclid_at_meteoritecentral.com>
Date: Mon, 14 Sep 2009 10:59:53 -0700 (PDT)
Message-ID: <170966.88311.qm_at_web33906.mail.mud.yahoo.com>

Sterling,
it is all but impossible for the earth to acquire a "comet moon" due to the orbital energies involved. Earth's gravity is much too small for this to occur. An asteroidal moon is much more probable and has actually happened. You may remember a few years ago when my colleague, Eric Christensen discovered 6R10DB9, which was Earth's first know "Second Moon". albeit a temporary one.

A good article and orbital diagram can be found on the Sky & Telescope site here:

http://www.skyandtelescope.com/news/home/7067527.html

Note Al Harris' comment about it being called a true "satellite".

--
Richard Kowalski
http://fullmoonphotography.net
IMCA #1081
--- On Mon, 9/14/09, Sterling K. Webb <sterling_k_webb at sbcglobal.net> wrote:
> From: Sterling K. Webb <sterling_k_webb at sbcglobal.net>
> Subject: [meteorite-list] Catch A Comet?
> To: "Meteorite List" <meteorite-list at meteoritecentral.com>
> Date: Monday, September 14, 2009, 10:00 AM
> It seems that not only do comets
> impact Jupiter,
> they may also become moons, temporary or
> permanent, of the planet.
> 
> Wonder what it would take to get a "comet moon"
> for the Earth?
> 
> Sterling K. Webb
> -------------------------------------------------------------------
> 
> http://www.space.com/scienceastronomy/090914-jupiter-comet.html
> Gotcha! Jupiter Turned Comet into a Moon By SPACE.com
> Staff
> 
> Jupiter already has an abundance of moons, but from 1949 to
> 1961 it had another, temporary satellite in the form of a
> comet trapped in the gas giant's gravitational grip.
> 
> Comet 147P/Kushida-Muramatsu was captured as a temporary
> moon of Jupiter in the mid-20th century and remained trapped
> in an irregular orbit for about twelve years, astronomers
> announced today.
> 
> There are only a handful of known comets where this
> phenomenon of temporary satellite capture has occurred and
> the capture duration in the case of Kushida-Muramatsu is the
> third longest.
> 
> The discovery was presented today at the European Planetary
> Science Congress in Potsdam by David Asher of Armagh
> Observatory in Northern Ireland.
> 
> An international team led by Katsuhito Ohtsuka of the Tokyo
> Meteor Network modeled the trajectories of 18 "quasi-Hilda
> comets," objects with the potential to go through a
> temporary satellite capture by Jupiter that results in them
> either leaving or joining the "Hilda" group of objects in
> the asteroid belt. Most of the cases of temporary capture
> were flybys, where the comets did not complete a full
> orbit.
> 
> But Kushida-Muramatsu was different: The team used recent
> observations tracking the comet over nine years to calculate
> hundreds of possible orbital paths for it over the previous
> century. In all scenarios, Kushida-Muramatsu completed two
> full revolutions of Jupiter, making it only the fifth
> captured orbiter to be identified.
> 
> "Our results demonstrate some of the routes taken by
> cometary bodies through interplanetary space that can allow
> them either to enter or to escape situations where they are
> in orbit around the planet Jupiter," Asher said.
> 
> Asteroids and comets can sometimes be distorted or
> fragmented by tidal effects induced by the gravitational
> field of a capturing planet, or may even impact with the
> planet. The most famous victim of both these effects was
> comet D/1993 F2 (Shoemaker-Levy 9), which was torn apart on
> passing close to Jupiter and whose fragments then collided
> with that planet in 1994. Previous computational studies
> have shown that Shoemaker-Levy 9 may well have been a
> quasi-Hilda comet before its capture by Jupiter.
> 
> "Fortunately for us Jupiter, as the most massive planet
> with the greatest gravity, sucks objects towards it more
> readily than other planets and we expect to observe large
> impacts there more often than on Earth. Comet
> Kushida-Muramatsu has escaped from the giant planet and will
> avoid the fate of Shoemaker-Levy 9 for the foreseeable
> future," Asher said.
> 
> The object that impacted with Jupiter this July, causing
> the new dark spot discovered by Australian amateur
> astronomer Anthony Wesley, may also have been a member of
> this class, even if it did not suffer tidal disruption like
> Shoemaker-Levy.
> 
> "Our work has become very topical again with the discovery
> this July of an expanding debris plume, created by the dust
> from the colliding object, which is the evident signature of
> an impact. The results of our study suggest that impacts on
> Jupiter and temporary satellite capture events may happen
> more frequently than we previously expected," Asher said.
> 
> The team has also confirmed a future moon of Jupiter. Comet
> 111P/Helin-Roman-Crockett, which has already orbited Jupiter
> three times between 1967 and 1985, is due to complete six
> laps of the giant planet between 2068 and 2086.
> 
> 
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Received on Mon 14 Sep 2009 01:59:53 PM PDT