Two nearby M dwarf binaries from the Two Micron All Sky Survey
Abstract
We report the discovery of two binary M dwarf systems in the immediate solar neighbourhood using the Two Micron All Sky Survey (2MASS). The first is an M6.5 companion to the nearby G star HD 86728 (Gl 376). The known properties of HD 86728 indicate that the M dwarf (Gl 376B) is old, metal-rich and only 14.9 parsec away. The M dwarf is highly active, with both Hα and X-ray emission. Thus, Gl 376B offers the opportunity to study an old, bright, active M dwarf with known metallicity, age and luminosity. We show that it is probable that Gl 376B is itself an unresolved pair. The other system consists of an M6.5 and an M8 dwarf with 14.5 arcsec separation. We estimate a distance of ∼16 parsec for this very low-mass pair. Stronger activity is observed in the M6.5 dwarf, supporting evidence that chromospheric activity is weakening near the hydrogen-burning limit.
Additional Information
© 2000 Royal Astronomical Society. Accepted 1999 August 24; Received 1999 July 28. Article first published online: 4 Apr. 2002. We thank Hartmut Jahreiû for discussion of the nature of Gl 376A and James Liebert for comments. This work was funded in part by NASA grant AST-9317456 and JPL contract 960847. JDK and AJB acknowledge the support of JPL, CalTech, which is operated under contract with NASA. INR and JDK acknowledge funding through a NASA/JPL grant to 2MASS Core Project science; AJB acknowledges support through this grant. This publication makes use of data products from 2MASS, which is a joint project of the University of Massachusetts and IPAC, funded by NASA and NSF. Some of the data presented herein were obtained at the Keck Observatory, which is operated as a scientific partnership by CalTech, the University of California and NASA. The Observatory was made possible by the generous financial support of the W. M. Keck Foundation. This research has made use of the Simbad data base, operated at CDS, Strasbourg, France.Attached Files
Published - GIZmnras00.pdf
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Additional details
- Eprint ID
- 27948
- Resolver ID
- CaltechAUTHORS:20111123-112913483
- AST-9317456
- NASA
- 960847
- JPL
- NASA/JPL/Caltech
- Created
-
2011-11-23Created from EPrint's datestamp field
- Updated
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2021-11-09Created from EPrint's last_modified field
- Caltech groups
- Infrared Processing and Analysis Center (IPAC)