NOAO >   Observing Info >   Approved Programs >   2009B-0057

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Proposal Information for 2009B-0057


PI: Kim Venn, University of Victoria, kvenn@uvic.ca
Address: Department of Physics and Astronomy, PO Box 3055, Victoria, BC, V8W 3P6, Canada

CoI: David Lambert, University of Texas at Austin
CoI: Thomas Puzia, Herzberg Institute for Astrophysics

Title: Search for Circumstellar Material around the Ultra Metal-Poor Stars

Abstract: The three "ultra metal-poor" stars HE1327-2326, HE0107-5240, and HE0557-4840, are thought to represent yields of the most metal-poor supernova and, therefore, observationally constrain the earliest stages of chemical evolution in the Universe. However, detailed comparison of their chemical compositions show remarkable similarities to chemically peculiar stars, which are stars with initially solar metallicities that now appear metal-poor due to a separation in their dust and gas components. If these stars are metal-poor due to chemical peculiarities only, then they are not fossils of the earliest epochs of chemical evolution in the Universe. A simple and definitive test of this hypothesis is to search for circumstellar material around them - even the null result is interesting since the absense of a dusty disk would confirm that these stars are truly metal-poor. While near-IR (JHK) colors show no near-IR excesses, the debris disks of most chemically peculiar stars do not outshine the star until beyond 10 microns (thus in the N and Q-bands). Thus, we propose Gemini-S TReCS N and Q-band imaging to test for the presence of circumstellar material around these stars.


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NOAO >   Observing Info >   Approved Programs >   2009B-0057

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