[meteorite-list] Meteorite Parent Bodies

From: AL Mitterling <almitt_at_meteoritecentral.com>
Date: Tue, 29 Jan 2008 11:57:41 -0500
Message-ID: <479F5B05.8060108_at_kconline.com>

Hello, Meteorite Parent Bodies,

Meteorites represent a picture into our past solar system. Some shed
more light on the past than others. Both carbonaceous chondrites and
ordinary chondrites (which are anything but ordinary) have been called
the rosetta stones of the solar system. Chondrites ARE unique specimens
which represent a jumbled up assortment of nebular dust, metallic
particles, and organic muck that holds the key to unlocking the secrets
of the solar system.

Chondrites are primitive matter that have escaped both severe geological
processes, radioactive decay or simply differentiation. This requires a
smaller parent body where processes of this nature didn't occur and
impacts that were small enough that the material wasn't changed (so it
could be delivered to Earth).

Although the study of meteorites dates back to the eighteenth century,
really much of our understanding of meteorites comes more from the mid
1900's when better scientific means were applied. In 1959 the first
pictures taken by multiple cameras (and by accident) were taken of the
fireball of an H5 meteorite that was later found and linking the
meteorites to the asteroid belt. The name of this meteorite was Pribram.
Several other networks also took shots of other fireballs coming down so
they could be tracked down and plotted. The names of these were Lost
City, OK, Farminton, Innisfree, and Dhajala. All plotting back to the
asteroid belt which suggested they were material coming from the
asteroid belt and possible remnants.

Comets have also been suggested to be sources for some meteorites but a
few problems exist to determine this. First very little is know about
comets (though we are just now finding out more) Two no photographs from
a network of cameras of material has been taken to show a relationship
of material to comets. The streaks of light during a meteor shower
represent only minor particles the size of dust or perhaps a bit larger.
So currently the jury is still out on pinning meteorite falls to known
comets or cometary debris.

Another way to confirm the ordinary chondrite and asteroid connection
has been through spectra. By comparing the absorption bands taken by
telescopes using a prism, the various components (chemical make up) of
asteroids can be compared
to meteorites. In a number of cases there are excellent matches. Such
matches have been made for asteroid 44, Nysa and the main aubrite
family, 4 Vesta and the eucrites, diogentites and howardites, 433 erros
and the L4 chondrites, 16 psyche and the E4's, and 1 Ceres and the CM2
chondrites.

Source: Meteorites and Their Parent Planets, by Harry Y. McSween Jr.

--AL Mitterling
Received on Tue 29 Jan 2008 11:57:41 AM PST