Precision Masses of the Low‐Mass Binary System GJ 623

Abstract

We have used aperture masking interferometry and adaptive optics (AO) at the Palomar 200 inch telescope to obtain precise mass measurements of the binary M dwarf GJ 623. AO observations spread over 3 yr combined with a decade of radial velocity measurements constrain all orbital parameters of the GJ 623 binary system accurately enough to critically challenge the models. The dynamical masses measured are m_{1}=0.371+/-0.015 M_{solar} (4%) and m_{2}=0.115+/-0.0023 M_{solar} (2%) for the primary and the secondary, respectively. Models are not consistent with color and mass, requiring very low metallicities.