Institute for Advanced Study Astrophysics Seminar

The vast data base produced by the Sloan Digital Sky Survey enables the identification and study of rare objects in sample sizes large enough to investigate their ensemble properties. This talk will include an overview of some of the work on stellar samples in the local galactic neighborhood, including: carbon-enhanced dwarf main sequence stars; low-mass metal-poor stars; close M-dwarf white-dwarf pairs and the role of of orbital angular momentum in enhancing stellar activity; and star formation in local dense and diffuse clouds. The large sample of carbon-enhanced dwarf stars makes it possible to derive a statistical luminosity function and align it with that of non-carbon-enriched dwarf stars. The carbon-enhanced dwarfs are the analogues of main-sequence K and early M stars but not of stars of about M3 and later, consistent with the increasing depth of the convection zone and atmospheric carbon enhancement due to mass transfer.