Hello Listers, Here is the third installment on the topic of nanodiamonds, and this one I can say can pull all 3 articles together so far and help bring them all circle.
Presolar grains from meteorites: Remnants from the early times of the solar system Katharina Lodders a,* and Sachiko Amari b a Planetary Chemistry Laboratory, Department of Earth and Planetary Sciences and McDonnell Center for the Space Sciences, Washington University, Campus Box 1169, One Brookings Drive, St. Louis, MO 63130, USA b Department of Physics and McDonnell Center for the Space Sciences, Washington University, Campus Box 1105, One Brookings Drive, St. Louis, MO 63130, USA Received 5 October 2004; accepted 4 January 2005 Abstract This review provides an introduction to presolar grains – preserved stardust from the interstellar molecular cloud from which our solar system formed – found in primitive meteorites. We describe the search for the presolar components, the currently known presolar mineral populations, and the chemical and isotopic characteristics of the grains and dust-forming stars to identify the grains’ most probable stellar sources. Keywords: Presolar grains; Interstellar dust; Asymptotic giant branch (AGB) stars; Novae; Supernovae; Nucleosynthesis; Isotopic ratios; Meteorites Introduction The history of our solar system started with the gravitational collapse of an interstellar molecular cloud laden with gas and dust supplied from dying stars. The dust from this cloud is the topic of this review. A small fraction of this dust escaped destruction during the many processes that occurred after molecular cloud collapse about 4.55 Ga ago. We define presolar grains as stardust that formed in stellar outflows or ejecta and remained intact throughout its journey into the solar system where it was preserved in meteorites. The survival and presence of genuine stardust in meteorites was not expected in the early years of meteorite studies. In the 1950s and 1960s, models of solar system formation assumed that the matter from the presolar molecular cloud was processed and homogenized (e.g., Suess 1965, see also Fegley 1993). Most of this matter accreted to the Sun and less than about one percent remained to formthe planets, their satellites, and other small objects (asteroids, Kuiper-Edgeworth-belt objects). During collapse and accretion of matter towards the cloud center, gravitational heating vaporized presolar solids, and it was generally assumed that this process resulted in a relatively homogeneous solar nebular gas made of evaporated presolar solids and presolar gas. Upon cooling of the solar nebula, new condensates appeared which accumulated to form the solid bodies in the solar system (Fig. 1). In this very simplified picture, all matter from the presolar cloud would be chemically and isotopically homogenized, and no record about the mineralogy of presolar solids would remain. Here is the link to the whole article http://arxiv.org/ftp/astro-ph/papers/0501/0501430.pdf Shawn Alan eBayshop http://shop.ebay.com/photophlow/m.html?_nkw=&_armrs=1&_from=&_ipg=&_trksid=p4340 ______________________________________________ Visit the Archives at http://www.meteoritecentral.com/mailing-list-archives.html Meteorite-list mailing list Meteorite-list@meteoritecentral.com http://six.pairlist.net/mailman/listinfo/meteorite-list
