[meteorite-list] Meteorite Parent Bodies

[AL Mitterling]

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