| Institution: | Department of Astronomy, University of Washington, Seattle, WA 98195, USA;Department of Astronomy, University of California, 601 Campbell Hall, Berkeley, CA 94720-3411, USA;Institute of Astronomy, University of Cambridge, Madingly Road, Cambridge CB3 0HA;Isaac Newton Group of Telescopes, Apartado de Correos 321, E-38700 Santa Cruz de la Palma, Canary Islands, Spain;Department of Astronomy, California Institute of Technology, Mail Code 105-24, 1200 East California Boulevard, Pasadena, CA 91125, USA;Department of Physics, Harvard University, 17 Oxford Street, Cambridge, MA 02138, USA;Infrared Processing and Analysis Centre, M/C 100-22, 770 S. Wilson Ave, Caltech, Pasadena, CA 91125, USA;Astronomisches Rechen-Institut/Zentrum für Astronomie der Universität Heidelberg, Mönchhofstrasse 12-14, 69120 Heidelberg, Germany;Department of Astronomy and Astrophysics, Pennsylvania State University, 525 Davey Laboratory, University Park, PA 16802, USA |
| Abstract: | We report on Two-Micron All-Sky Survey (2MASS) J01542930+0053266, a faint eclipsing system composed of two M dwarfs. The variability of this system was originally discovered during a pilot study of the 2MASS Calibration Point Source Working Data base. Additional photometry from the Sloan Digital Sky Survey yields an eight-passband light curve from which we derive an orbital period of 2.639 0157 ± 0.000 0016 d. Spectroscopic followup confirms our photometric classification of the system, which is likely composed of M0 and M1 dwarfs. Radial velocity measurements allow us to derive the masses (M1= 0.66 ± 0.03 M⊙; M2= 0.62 ± 0.03 M⊙) and radii (R1= 0.64 ± 0.08 R⊙; R2= 0.61 ± 0.09 R⊙) of the components, which are consistent with empirical mass–radius relationships for low-mass stars in binary systems. We perform Monte Carlo simulations of the light curves which allow us to uncover complicated degeneracies between the system parameters. Both stars show evidence of Hα emission, something not common in early-type M dwarfs. This suggests that binarity may influence the magnetic activity properties of low-mass stars; activity in the binary may persist long after the dynamos in their isolated counterparts have decayed, yielding a new potential foreground of flaring activity for next generation variability surveys. |
