[meteorite-list] Extra-solar material?

From: Norbert Classen <riffraff_at_meteoritecentral.com>
Date: Sun, 4 May 2008 19:36:08 +0200
Message-ID: <000501c8ae0d$57ad1d30$2002a8c0_at_lunatic>

Hi Matthias, and All,

You asked:

> isn't presolar extrasolar too, in a certain sense?

Not necessarily, at least not how I understand it. I've read some abstracts
and papers that say, e.g., that not all presolar nano diamonds in Allende,
and other carbonaceous chondrites are considered to be of interstellar or
"extra-solar" origin. So some presolar grains are interstellar, and some or
not. However, interstellar grains found in meteorites should be considered
presolar as they would have to be incorporated into meteorites in the early
days of our own solar nebula. Please correct me if I'm wrong.

BTW, I found a few abstracts dealing with interstellar grains, i.e., real
"stardust" in primitive meteorites, carbonaceous chondrites, and IDPs
(Interplanetary Dust Particles). Here are three examples that show that some
meteorites contain real stardust, i.e., actual grains of novea, supernovae,
RGB (red giant branch), AGB (asymptotic giant branch), or Wolf-Rayet stars.
So, as I said before, we surely have plenty of "extra-solar"/interstellar
stuff in our collections, but just as microscopically small inclusions:

http://www.journals.uchicago.edu/doi/abs/10.1086/510612
http://adsabs.harvard.edu/abs/1993Metic..28..490A
http://adsabs.harvard.edu/abs/1997ApJ...483..475N

Fascinating, isn't it? You will certainly view your Tieschitz, or your Acfer
094 with different eyes now ;-)

All the best,
Norbert

-----Urspr?ngliche Nachricht-----

Hi Norbert, list , -

isn't presolar extrasolar too, in a certain sense?

See f.e.: http://www.psrd.hawaii.edu/Dec02/TagishLake.html

Best,

Matthias

----- Original Message -----

Hi Mark,

The nano diamonds in Allende CAI's are considered to be samples of
extra-solar origin; at least they show isotopic values that don't match with
any of the other values measured for materials of our solar system
(including meteorites).

I believe there were studies of other (Antarctic) carbonaceous chondrites
which also were shown to be from other systems, but right now I don't
remember the exact publication. Should have been in MAPS, but I would have
to look this up, first. Bernd: do you have an idea where I might have read
about it?

But as far as I know no meteorite as such has been considered as
"extra-solar", so far - these are always inclusions, and most of them are
microscopically small.

All the best,
Norbert

-----Urspr?ngliche Nachricht-----

I'm reading Paul Davies' "The Fifth Miracle". In chapter 6 it refers to the
1996 discovery by Taylor, Baggaley and Steel of inter-stellar dust particles
entering the earth's atmosphere in the form of fast (>
70-km/s) meteors:

http://www.nature.com/nature/journal/v380/n6572/abs/380323a0.html

It got me wondering as to whether there are any candidates for meteorites
which may be of extra-solar origin. Are there any? How would they be
identified - a suspiciously long CRE age would perhaps be one indicator?

Mark

--
Mark's Meteorite Pages: http://meteorites.cc
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Received on Sun 04 May 2008 01:36:08 PM PDT