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Re: (meteorobs) Re: Meteoroid Size



In a message dated 98-09-30 19:33:25 EDT, you write:

<< 
 All major annual showers, except perhaps the Geminids, originated from
 comets. Since the density of the average Geminid is not that much
 greater than that of the average Perseid meteoroid it would be safe to
 guess that the asteroid 1983TB (parent body of the Geminids) was once a
 comet. >>

I believe Petr Pravec of the Astronomical Institute in the Czech Republic
posted sometime in late august that the parent source of the Geminids
(asteroid 3200 Phaethon) was determined to have a density of 3-4 g/cm^3. This
was derived from an analysis of the atmospheric penetration behavior of 41
Geminid fireballs. Their behavior resembled that of fireballs producing stony
meteorites. The average density of stony meteorites is around 3.54 g/cm^3.
That of comets is around 0.3 to 0.6 g/cm^3. It would seem that the parent
source of the Geminids and that of stony meteorites might have something in
common? Unless perseids have densities near that of stony meteorites, I don't
see their density being really that close?
George Zay