Faint high-latitude carbon stars discovered by the sloan digital sky survey: An initial catalog

Ronald A. Downes, Bruce Margon, Scott F. Anderson, Hugh C. Harris, G. R. Knapp, Josh Schroeder, Donald P. Schneider, Donald G. York, Jeffery R. Pier, J. Brinkmann

Research output: Contribution to journalArticlepeer-review

50 Scopus citations

Abstract

A search of more than 3000 deg 2 of high-latitude sky by the Sloan Digital Sky Survey has yielded 251 faint high-latitude carbon stars (FHLCs), the large majority previously uncataloged. We present homogeneous spectroscopy, photometry, and astrometry for the sample. The objects lie in the 15.6 < r < 20.8 range and exhibit a wide variety of apparent photospheric temperatures, ranging from spectral types near M to as early as F. Proper-motion measurements for 222 of the objects show that at least 50%, and quite probably more than 60%, of these objects are actually low-luminosity dwarf carbon (dC) stars, in agreement with a variety of recent, more limited investigations that show that such objects are the numerically dominant type of star with C 2 in the spectrum. This SDSS homogeneous sample of ∼110 dC stars now constitutes 90% of all known carbon dwarfs and will grow by another factor of 2-3 by the completion of the survey. As the spectra of the dC and the faint halo giant C stars are very similar (at least at spectral resolution of 10 3), despite a difference of 10 mag in luminosity, it is imperative that simple luminosity discriminants other than proper motion be developed. We use our enlarged sample of FHLCs to examine a variety of possible luminosity criteria, including many previously suggested, and find that, with certain important caveats, JHK photometry may segregate dwarfs and giants.

Original languageEnglish (US)
Pages (from-to)2838-2849
Number of pages12
JournalAstronomical Journal
Volume127
Issue number5 1781
DOIs
StatePublished - May 2004

All Science Journal Classification (ASJC) codes

  • Astronomy and Astrophysics
  • Space and Planetary Science

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