[meteorite-list] Questions about accretion.

From: GeoZay at aol.com <GeoZay_at_meteoritecentral.com>
Date: Sun, 5 Apr 2009 15:19:09 EDT
Message-ID: <be6.483742dc.370a5e2d_at_aol.com>

>>How long does the formation of meteoroid bodies and larger asteroids
take?<<

I really don't know, but gonna throw out a guess. I'm assuming that in the
beginning of star and planet formation, there is a lot of dust around. I
recall an experiment aboard one of the Shuttles or space station where a lot of
fine material such as talcum powder was floating around weightless in a
container. I guess there was amazement about how this material was clumping very
fast due to electrostatic charges. Based on that scenario, I'd have to guess
that we can expect to see fist sized clumps in about a month maybe? I'd imagine
eventually gravity itself will have to get into the picture as well. Overall,
I wouldn't think it would take too many years for asteroid sized bodies to
form...as long as there are a lot of raw material available.

>>How does the iron migrate to the core?<<

Again I don't really know, but will throw out a guess for someone to work me
over with. :O) I'm assuming that the iron will have to melt in order for
this differentiation to occur. I guess there will also have to be a minimum
sized asteroid in order for iron to melt so it can migrate. Okay...what could
melt the iron then? Things that comes to mind is the heat from radioactive
elements; Heat from compression; heat generated if the asteroid is in a strong
magnetic field around the sun (like the moon Io around Jupiter); and heat from
impacts as well. then it becomes sorta like gold in a pan...the heavies at the
bottom or middle and lighter material on top...but in this case without the
melting.

>>Do all "large" asteroids consist of an iron core surrounded by lighter
materials further towards the asteroids surface?<<

My guess...if there was some internal melting, I'd say yes.


>> If a meteoroid is a small part of a larger asteroid, wouldn't all
asteroids
once have been meteoroids by definition during their formation within
solar nebulae?<<

I'd say yes to those that formed from dust. But if a solar nebula is the
remnants of previous stars that went supernova, I would imagine there could be a
fair amount of asteroids left over from that explosion as well. I don't
really know. If that was right, I'd expect to hear about a few meteorites that
were older than our solar system...unless our solar system formation began very
fast after it's source of material from a supernova occurred showing a near
similar age.
GeoZay

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Received on Sun 05 Apr 2009 03:19:09 PM PDT