The dM4.5e star G124-62 and its binary L dwarf companion DENIS-P J1441-0945. Common proper motion, distance, age, and masses

Abstract

We present astrometric and photometric measurements of the field binary L1 dwarf DENIS-P J1441-0945. Analysis of archival HST images and photometric parallax measurements give a distance of 34±7 pc and a proper motion close to that of the nearby high proper motion star G124-62. Comparison of SuperCOSMOS and 2MASS images confirms that these objects form a common proper motion pair, while spectroscopy of G124-62 shows it to be a dM4.5e star. The kinematics show that this system is a member of the Hyades supercluster. The resulting age constraints for the system are 500-800 Myr and the mass of each component of DENIS-P J1441-0945 is 0.072^+0.010_-0.018 {M_⊙}.