[WWW] Planets like earth may have formed around other stars, UCLA astronomers report

The chemical fingerprint of a burned-out star indicates that Earth-
like planets may not be rare in the universe and could give clues to
what our solar system will look like when our sun dies and becomes a
white dwarf star some five billion years from now.

http://theanalystmagazine.com/pr/k112.html

wrote:
The chemical fingerprint of a burned-out star indicates that Earth-
like planets may not be rare in the universe and could give clues to
what our solar system will look like when our sun dies and becomes a
white dwarf star some five billion years from now.

http://theanalystmagazine.com/pr/k112.html

For a more technical account of this work, see arXiv:0708.0198
(Ap.J, in press).
Title: The Chemical Composition of an Extrasolar Minor Planet
Abstract:
We report the relative abundances of 17 elements in the atmosphere of
the white dwarf star GD 362, material that, very probably, was contained
previously in a large asteroid or asteroids with composition similar
to the Earth/Moon system. The asteroid may have once been part of a
larger parent body not unlike one of the terrestrial planets of our
solar system.

I skimmed through this paper. To me, the weakest link seemed to be
the attribution of the observed abundances to a recent asteroid-accretion
event. If anyone in s.a.r is an expert on this sort of work, I'd be
interested in commentary on how plausible or probable this scenario
is, in comparison with other possible formation scenarios. The paper
has some discussion of this, but mostly devoted to arguing that other
scenarios are unlikely -- I didn't see a quantitative analysis of how
the asteroid-accretion scenario is.

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-- Jonathan Thornburg (remove -animal to reply)
School of Mathematics, U of Southampton, England
"Washing one's hands of the conflict between the powerful and the
powerless means to side with the powerful, not to be neutral."
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