NOAO >   Observing Info >   Approved Programs >   2005B-0154

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Proposal Information for 2005B-0154


PI: Eileen Friel, National Science Foundation, efriel@nsf.gov
Address: Division of Astronomical Sciences, 4201 Wilson Blvd, Arlington, VA 22230, USA

CoI: Heather Jacobson, Indiana University
CoI: Bruce Carney, University of North Carolina
CoI: Caty Pilachowski, Indiana University
CoI: David Yong, University of North Carolina
CoI: Ken Janes, Boston University

Title: The Origin of the Galaxy's Outer Disk

Abstract: The outer Galactic disk appears to have experienced a very different chemical evolution history than has the solar neighborhood, based on recent analyses of [Fe/H] and [(alpha)/Fe] for eight clusters with R_gc > 11 kpc. The expected metallicity gradient levels out and the abundances of the lighter elements, produced in Type II SNe, rise relative to iron. The results may be interpreted as evidence of a Galactic disk that has grown significantly with time, but this interpretation requires additional clusters whose ages and chemical abundances and abundance patterns can be determined. We request time here to observe red giants in clusters in the critical transition region R_gc ~ 10 to 12 kpc.


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NOAO >   Observing Info >   Approved Programs >   2005B-0154

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