NLTT 41135: A Field M Dwarf + Brown Dwarf Eclipsing Binary in a Triple System, Discovered by the MEarth Observatory
We report the discovery of an eclipsing companion to NLTT 41135, a nearby M5 dwarf that was already known to have a wider, slightly more massive common proper motion companion, NLTT 41136, at 2".4 separation. Analysis of combined-light and RV curves of the system indicates that NLTT 41135B is a (31-34) ± 3M_(Jup) brown dwarf (where the range depends on the unknown metallicity of the host star) on a circular orbit. The visual M dwarf pair appears to be physically bound, so the system forms a hierarchical triple, with masses approximately in the ratio 8:6:1. The eclipses are grazing, preventing an unambiguous measurement of the secondary radius, but follow-up observations of the secondary eclipse (e.g., with the James Webb Space Telescope) could permit measurements of the surface brightness ratio between the two objects, and thus place constraints on models of brown dwarfs.
Additional Information© 2010 American Astronomical Society. Received 2010 February 23; accepted 2010 June 8; published 2010 July 14. The MEarth team gratefully acknowledges funding from the David and Lucile Packard Fellowship for Science and Engineering (awarded to DC). This material is based upon work supported by the National Science Foundation under grant number AST-0807690. L.B. and D.W.L. acknowledge partial support from the NASA Kepler mission under cooperative agreement NCC2-1390. J.A.J. thanks the NSF Astronomy and Astrophysics Postdoctoral Fellowship program for support in the years leading to the completion of this work, and acknowledges support from NSF grant AST-0702821. We thank Isabelle Baraffe for providing NextGen and cond models in the z band, Daniel Fabrycky for helpful discussions regarding dynamics, and Timothy Brown and the rest of the team at the Las Cumbres Observatory Global Telescope for their efforts in trying to obtain a resolved light curve of the system. The MEarth team is greatly indebted to the staff at the Fred Lawrence Whipple Observatory for their efforts in construction and maintenance of the facility, and would like to explicitly thank Wayne Peters, Ted Groner, Karen Erdman-Myres, Grace Alegria, Rodger Harris, Bob Hutchins,Dave Martina, Dennis Jankovsky, and Tom Welsh for their support. Finally, we thank the referee for a thorough and helpful report, which has substantially improved the manuscript. This research is based on observations made with the Nordic Optical Telescope, operated on the island of La Palma jointly by Denmark, Finland, Iceland, Norway, and Sweden, in the Spanish Observatorio del Roque de los Muchachos of the Instituto de Astrofisica de Canarias. This research has made extensive use of data products from the Two Micron All Sky Survey, which is a joint project of the University of Massachusetts and the Infrared Processing and Analysis Center/California Institute of Technology, funded by NASA and the NSF, NASA's Astrophysics Data System (ADS), and the SIMBAD database, operated at CDS, Strasbourg, France. The Digitized Sky Surveys were produced at the Space Telescope Science Institute under U.S. Government grant NAG W-2166. The images of these surveys are based on photographic data obtained using the Oschin Schmidt Telescope on Palomar Mountain and the UK Schmidt Telescope. The plates were processed into the present compressed digital form with the permission of these institutions. Funding for the SDSS and SDSS-II has been provided by the Alfred P. Sloan Foundation, the Participating Institutions, the National Science Foundation, the U.S. Department of Energy, the National Aeronautics and Space Administration, the Japanese Monbukagakusho, the Max Planck Society, and the Higher Education Funding Council for England. The SDSS Web Site is http://www.sdss.org/. The SDSS is managed by the Astrophysical Research Consortium for the Participating Institutions. The Participating Institutions are the American Museum of Natural History, Astrophysical Institute Potsdam, University of Basel, University of Cambridge, Case Western Reserve University, University of Chicago, Drexel University, Fermilab, the Institute for Advanced Study, the Japan Participation Group, Johns Hopkins University, the Joint Institute for Nuclear Astrophysics, the Kavli Institute for Particle Astrophysics and Cosmology, the Korean Scientist Group, the Chinese Academy of Sciences (LAMOST), Los Alamos National Laboratory, the Max-Planck-Institute for Astronomy (MPIA), the Max-Planck-Institute for Astrophysics (MPA), New Mexico State University, Ohio State University, University of Pittsburgh, University of Portsmouth, Princeton University, the United States Naval Observatory, and the University of Washington. The authors wish to recognize and acknowledge the very significant cultural role and reverence that the summit of Mauna Kea has always had within the indigenous Hawaiian community. We are most fortunate to have the opportunity to conduct observations from this mountain. Facilities: UH:2.2m (OPTIC), FLWO:1.2m (KeplerCam), FLWO:1.5m (TRES), NOT (FIES)
Published - 0004-637X_718_2_1353.pdf