[meteorite-list] Chondritic parent bodies

From: Richard Kowalski <kowalski_at_meteoritecentral.com>
Date: Wed, 09 Sep 2009 09:48:51 -0700
Message-ID: <4AA7DC73.8060901_at_lpl.arizona.edu>

This paper in Astronomy & Astrophysics may be of interest:

http://tinyurl.com/laupyx

It discusses the identification of several new, very young asteroid
families called Datura, Emilkowalski, 1992YC2, and Lucascavin clusters.

These objects are the largest members of these new families and are
450+/-50 thousand years (ky), 220+/-30 ky, 50-250 ky, and 200-600 ky
old, respectively.

As you see, the spectrum of Datura and H4 chondrites are extremely similar.


(A personal comment, Emilkowalski is the sole mainbelt asteroid that I
discovered from my backyard observatory when I was an amateur and is
named for my late father)

-- 
Richard Kowalski
Catalina Sky Survey
Lunar and Planetary Laboratory
University of Arizona
Tucson, AZ  85721
--- On Wed, 9/9/09, Alan Rubin <aerubin at ucla.edu> wrote:
 > From: Alan Rubin <aerubin at ucla.edu>
 > Subject: Re: [meteorite-list] Chondritic parent bodies
 > To: dave at fallingrocks.com, "'Meteorite List'" 
<meteorite-list at meteoritecentral.com>
 > Date: Wednesday, September 9, 2009, 9:23 AM
 > The general supposition is that all L
 > chondrites come from one parent body, that H chondrites come
 > from another, etc.  We don't know this to be strictly
 > true, but there is evidence that it is broadly true.
 > For example, about two-thirds of all L chondrites (of
 > different petrologic types) were shocked about 470 Ma ago or
 > so, indicating that they were on the same parent body at
 > that time.  Similarly, nearly half of all H chondrites
 > (of different petrologic types) have a cosmic-ray exposure
 > age of about 7.5 Ma indicating that they were all within
 > about a kilometer of each other (or so) at that time.
 > The idea that the parent bodies were stratified with the
 > type-6 chondrites in the center and type-5s closer to the
 > surface, etc. is known as the onion shell model.  There
 > is some evidence for it and some against it. Hence, some
 > researchers are strong advocates and others reject the
 > model. As is clear, the situation is not yet resolved.
 > Alan Rubin
 >
 > ----- Original Message ----- From: "Dave Gheesling" 
<dave at fallingrocks.com>
 > To: "'Meteorite List'" <meteorite-list at meteoritecentral.com>
 > Sent: Tuesday, September 08, 2009 8:40 PM
 > Subject: [meteorite-list] Chondritic parent bodies
 >
 >
 > > All,
 > > Pete's question re: pallasites reminds me of one I've
 > been meaning to throw
 > > out to the group for a while.  I believe that, by
 > definition, L6's come from
 > > one parent body and L5's, say, come from
 > another.  It's clear why breccias
 > > might simply be an association of the two.  But
 > I've seen cross section
 > > illustrations of hypothetical asteroids more than once
 > which indicate a
 > > transitional progression from L3 material at the
 > exterior/crust through L4,
 > > then L5, and eventually to L6 at the
 > center/core.  Presumably this is due to
 > > insulative properties and the like towards the
 > interior which allow more
 > > heat from radioactivity to build up, etc, but this
 > also seems to indicate a
 > > single parent body.  I'm sure Sterling & Co.
 > might have a field day with
 > > this one, and I'm looking forward to any responses out
 > there...
 > > Thanks much,
 > > Dave
 > >
 > > Dave Gheesling
 > > IMCA #5967
 > > www.fallingrocks.com

Received on Wed 09 Sep 2009 12:48:51 PM PDT