A search of more than 3000 deg2 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 C2 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 103), 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.
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机译：Sloan Digital Sky Survey对3000摄氏度以上的高纬度天空进行了搜索，结果产生了251个微弱的高纬度碳星（FHLC），其中大多数以前没有被列入目录。我们介绍了样品的均相光谱法，光度法和天体法。这些物体位于15.6 展开▼
