Discovery of the Widest Very Low Mass Binary

Abstract

We report the discovery of a very low mass binary system (primary mass <0.1 Msol) with a projected separation of ~5100 AU, more than twice that of the widest previously known system. A spectrum covering the 1-2.5 microns wavelength interval at R ~1700 is presented for each component. Analysis of the spectra indicates spectral types of M6.5V and M8V, and the photometric distance of the system is ~62 pc. Given that previous studies have established that no more than 1% of very low mass binary systems have orbits larger than 20 AU, the existence of such a wide system has a bearing on very low mass star formation and evolution models