AW: AW: [meteorite-list] There are no silly questions? Wait until youhaveread that :-)

From: star-bits_at_comcast.net <star-bits_at_meteoritecentral.com>
Date: Fri Oct 22 13:02:40 2004
Message-ID: <102220041702.15723.41793D2B00018CBD00003D6B22007348309C9B070DD39D0E9B9C_at_comcast.net>

Jörn Koblitz worte:

<A good question which I don't have an answer to. In terms of orbital evolution
and probabilities to be catched up the larger solar system bodies, I do not se a
reason, why iron meteoroids shall survive longer than stony meteoroids. May be,
the differences in CRE ages are a result of cosmic-ray shielding effects. Does
someone else has a good idea to explain these differences?>

One of the most effective long term forces moving asteroids is the Yarkovsky effect. When
a photon leaves the asteroid during cooling it pushes away giving the asteroid a tiny
momentum change. Because the afternoon side is hotter than the morning side and
the early night side is hotter than the late night side there is a sideways acceleration
on the asteroid causing orbit change. The force is tiny, but because it is constant it
can make big changes in orbits.

For two bodies of the same shape, size and albedo the Yankovsky force would be the
same. However, iron asteroids are much denser than stony asteroids so the same
force would result in a smaller acceleration and the change in their orbits would be less.
As a result iron asteroids would remain in stable orbits longer and hang around in the
inner solar system longer.

--
Eric Olson
ELKK Meteorites
http://www.star-bits.com

Received on Fri 22 Oct 2004 01:02:35 PM PDT