[meteorite-list] Who Pulled the Trigger: a Supernova or an AGB Star?

From: Shawn Alan <photophlow_at_meteoritecentral.com>
Date: Sat, 5 Jun 2010 21:07:49 -0700 (PDT)
Message-ID: <529396.81008.qm_at_web35402.mail.mud.yahoo.com>

Hello Listers,

Have you wondered what came first, the Supernova or AGB Star ejections? If so this article has a broad explanation on the when and the how our Solar system came to be.
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Here is an abstract from the article and the introduction:
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Who Pulled the Trigger: a Supernova or an AGB Star?
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Alan P. Boss and Sandra A. Keiser
Department of Terrestrial Magnetism, Carnegie Institution of Washington, 5241 Broad
Branch Road, NW, Washington, DC 20015-1305
boss at dtm.ciw.edu, keiser at dtm.ciw.edu
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ABSTRACT
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The short-lived radioisotope 60Fe requires production in a core collapse supernova or AGB star immediately before its incorporation into the earliest solar system solids. Shock waves from a somewhat distant supernova, or a relatively nearby AGB star, have the right speeds to simultaneously trigger the collapse of a dense molecular cloud core and to inject shock wave material into the resulting protostar. A new set of FLASH2.5 adaptive mesh refinement hydrodynamical models shows that the injection efficiency depends sensitively on the assumed shock thickness and density. Supernova shock waves appear to be thin enough to inject the amount of shock wave material necessary to match the short-lived
radioisotope abundances measured for primitive meteorites. Planetary nebula
shock waves from AGB stars, however, appear to be too thick to achieve the
required injection efficiencies. These models imply that a supernova pulled the trigger that led to the formation of our solar system.
Subject headings: hydrodynamics ? instabilities ? planets and satellites: formation ? stars: formation
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1. Introduction

Primitive meteorites contain daughter products of the decay of short-lived radioisotopes (SLRIs) such as 26Al, 41Ca, 53Mn, and 60Fe, distributed in different minerals in a way that indicates the parent isotopes were still alive at the time of their incorporation into the refractory inclusions and chondrules that record the earliest history of the solar system. The presence of 60Fe is particularly significant, as its production requires stellar nucleosynthesis (Tachibana & Huss 2003; Tachibana et al. 2006). Given half-lives on the order of  106 yr, the evidence for these radioisotopes suggests that the same stellar source that synthesized them may well have triggered the collapse of the presolar dense cloud core as well, while simultaneously injecting the freshly-synthesized radioisotopes (Cameron & Truran 1977; Boss 1995). Supernovae resulting from massive stars in the range of  20M to  60M or planetary nebulae derived from intermediate-mass ( 5M )
 AGB stars have been proposed as possible sources of all or most of these radioisotopes (e.g., Huss et al. 2009).
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The link to the whole article:
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http://arxiv.org/PS_cache/arxiv/pdf/1005/1005.3981v1.pdf
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Shawn Alan
IMCA 1633
eBaystore
http://shop.ebay.com/photophlow/m.html?_nkw=&_armrs=1&_from=&_ipg=&_trksid=p4340
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Received on Sun 06 Jun 2010 12:07:49 AM PDT


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