Discovery of the widest very low mass field binary.
RADIGAN J., LAFRENIERE D., JAYAWARDHANA R. and DOYON R.
Abstract (from CDS):
We present the discovery of the widest (∼6700 AU) very low mass (VLM) field binary to date, found in a proper motion cross-match of the Sloan Digital Sky Survey and the Two Micron All Sky Survey. Our follow-up J-band imaging provides a 10 year baseline for measuring proper motions. Consequently, we are able to confirm the common proper motion of the pair to within 10 mas, implying a 99.5% probability of their physical association. Near-infrared spectra of the components indicate spectral types of M6±1 and M7±1. The system resides at a spectroscopic distance of 105±13 pc and has an angular separation of 63".38±0".05. We have used evolutionary models to infer component masses of 0.105+0.029–0.017M☉ and 0.091+0.010–0.007M☉. The large separation and low binding energy of this system can provide constraints for formation models of VLM stars.