A dusty M5 binary in the β Pictoris moving group

¹ Departamento de AstronomíaUniversidad de Chile, Casilla 36-D Santiago, Chile
e-mail: drodrigu@das.uchile.cl
² Dept. of Physics & Astronomy, University of California, Los Angeles 90095, USA
³ Dept. of Terrestrial Magnetism, Carnegie Institution of Washington, 5241 Broad Branch Road NW, Washington DC 20015, USA

Received: 10 February 2014
Accepted: 8 April 2014

Abstract

We report the identification of a new wide separation binary (LDS 5606) in the ~20 Myr-old β Pic moving group. This M5+M5 pair has a projected separation of 26′′, or ~1700 AU at a distance of 65 pc. Both stars host warm circumstellar disks and many strong hydrogen and helium emission lines. Spectroscopic observations reveal signatures of youth for both stars and on-going mass accretion in the primary. The properties of LDS 5606 make it an older analog to the ~8 Myr TWA 30 system, which is also composed of a pair of widely separated mid-M dwarfs, each hosting their own warm circumstellar disks. The binary star LDS 5606 joins a rather exclusive club of only three other known binary systems, far from any molecular cloud, where both members are orbited by detected circumstellar disks.