[meteorite-list] Vesta

From: Galactic Stone & Ironworks <meteoritemike_at_meteoritecentral.com>
Date: Fri, 16 Jan 2015 12:59:34 -0500
Message-ID: <CAKBPJW_YoLQ0OjHghMkPVmKDZ7czQEekwAAAP_T8pdf_f9fHeA_at_mail.gmail.com>

Hi Andre,

Even before the NASA Dawn program, scientists had made a strong
connection between the HED meteorites and Vesta. The brief paper at
the link below gives a general explanation of the connection. In the
years since, Dawn has solidified that connection.

>From the text :

Many lines of evidence indicate that
meteorites are derived from the asteroid belt but, in
general, identifying any meteorite class with a particular
asteroid has not been possible. One exception
is asteroid 4 Vesta, where a strong case can be made
that it is the ultimate source of the howardite-eucritediogenite
(HED) family of basaltic achondrites. Visible
and near infrared reflectance spectra (Fig. 2) first
pointed to a connection between Vesta and the basaltic
achondrites [4]. Experimental petrology demonstrated
that the eucrites (the relatively unaltered and unmixed
basaltic achondrites) were the product of approximately
a 10% melts [5]. Studies of siderophile element
partitioning suggested that this melt was the residue
of an asteroidal-scale magma ocean [6]. Mass
balance considerations point to a parent body that had
its surface excavated, but remains intact [7]. Modern
telescopic spectroscopy has identified kilometer-scale
"Vestoids" between Vesta and the 3:1 orbit-orbit resonance
with Jupiter [8]. Dynamical simulations of impact
into Vesta demonstrate the plausibility of ejecting
relatively unshocked material at velocities consistent
with these astronomical observations [9]. Hubble
Space Telescope images (Fig. 3) show a 460 km diameter
impact basin at the south pole of Vesta [10].
Spectroscopic studies of near-Earth asteroids revealed
three small objects with basaltic composition which are
arguably the proximal source of the HED meteorites,
having reached one of Jupiter's resonances faster than
the objects observed by [10] after which they quickly
evolved into Mars crossing objects and then near-Earth
objects. [11].

Hope this helps.

Best regards,

MikeG

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On 1/16/15, Deborah Anne K. Martin via Meteorite-list
<meteorite-list at meteoritecentral.com> wrote:
> Hello all,
>
> Could someone explain to me exactly how it was determined that certain
> meteorites, like Tatahouine, originally came from Vesta ?
>
> I appreciate the help.
>
> Andre
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Received on Fri 16 Jan 2015 12:59:34 PM PST