A new low-mass eclipsing binary from SDSS-II

We present observations of a new low-mass, double-lined eclipsing binary system discovered using repeat observations of the celestial equator from the Sloan Digital Sky Survey II. Using near-infrared photometry and optical spectroscopy we have measured the properties of this short-period [P = 0.407037(14) days] system and its two components. We find the following parameters for the two components: M-1 = 0.272 +/- 0.020 M-circle dot, R-1 = 0.268 +/- 0.010 R-circle dot, M-2 = 0.240 +/- 0.022 M-circle dot, R-2 - 0.248 +/- 0.0090 R-circle dot, T-1 - 3320 +/- 130 K, and T-2 - 3300 +/- 130 K. The masses and radii of the two components of this system agree well with theoretical expectations based on models of low-mass stars, within the admittedly large errors. Future synoptic surveys like Pan-STARRS and LSST ill produce a wealth of information about low-mass eclipsing systems and should make it possible, with an increased reliance on follow-up observations, to detect many systems with low-mass and substellar companions. With the large numbers of objects for which these surveys will produce high-quality photometry, we suggest that it becomes possible to identify such systems even with sparse time sampling and a relatively small number of individual observations.