The Lowest Metallicity Stars from SDSS/SEGUE

Beers, Timothy C.; Lee, Y. S.; Peruta, C.; Sivarani, T.; Allende Prieto, C.; Aoki, W.; Carollo, D.; SDSS
Bibliographical reference

American Astronomical Society, AAS Meeting #213, #416.12; Bulletin of the American Astronomical Society, Vol. 41, p.228

Advertised on:
1
2009
Number of authors
8
IAC number of authors
0
Citations
2
Refereed citations
2
Description
The first extension of the Sloan Digital Sky Survey (SDSS-II), which included the program SEGUE: Sloan Extension for Galactic Understanding and Exploration, ended in July, 2008. This effort has already produced the largest sample of medium-resolution stellar spectra yet obtained. These data are revolutionizing our understanding of the nature of the stellar populations of the Milky Way, in particular that of the halo populations. The SEGUE Stellar Parameter Pipeline (SSPP) has obtained estimates of the atmospheric parameters (Teff, log g, [Fe/H]) for more than half of the spectra to date, totaling in excess of 200,000 stars (not all stars observed in SDSS/SEGUE have colors that are amenable to definitive determination of their atmospheric parameters). Here we report on the distribution of stellar metallicity, [Fe/H], for stars in the SDSS/SEGUE database with [Fe/H] < -2. This sample now exceeds 15,000 stars, more than triple the number of such stars discovered by all previous surveys combined. We also comment on the prospects for further increases in this sample in the near future, from the next extension of SDSS (SDSS-III), now underway, which includes a full year of SEGUE operation from July 2008 to July 2009, and additional "piggy back” observations of stars taken during subsequent years. This work was supported in part by grants PHY 02-16783 and PHY 08-22648: Physics Frontiers Center / Joint Institute for Nuclear Astrophysics (JINA), awarded by the U.S. National Science Foundation.