A Second Stellar Color Locus: a Bridge from White Dwarfs to M stars
/ Authors
V. Smolčić, Ž. Ivezić, G. Knapp, R. Lupton, K. Pavlovski, S. Ilijić, D. Schlegel, J. A. Smith, P. McGehee, N. Silvestri
and 7 more authors
S. Hawley, C. Rockosi, J. Gunn, M. Strauss, Xiaohui Fan, D. Eisenstein, H. Harris
/ Abstract
We report the discovery of a locus of binary stars in the Sloan Digital Sky Survey (SDSS) g-r versus u-g color-color diagram that connects the colors of white dwarfs and M dwarfs. While its contrast with respect to the main stellar locus is only ~1 : 2300, this previously unrecognized feature includes 863 stars from the SDSS Data Release 1 (DR1). The position and shape of the feature are in good agreement with predictions of a simple binary star model that consists of a white dwarf and an M dwarf, with the components' luminosity ratio controlling the position along this binary system locus. SDSS DR1 spectra for 47 of these objects strongly support this model. The absolute magnitude-color distribution inferred for the white dwarf component is in good agreement with the models of Bergeron et al.
Journal: The Astrophysical Journal Letters
DOI: 10.1086/426475