Gemini Preprint #3

The Solar Neighborhood III: A Near Infrared Search for Widely Separated Low Mass Binaries

D. A. Simons
Gemini Telescopes Project, 950 N. Cherry Ave., Tucson AZ 85719

Todd J. Henry
Space Telescope Science Institute, 3700 San Martin Drive, Baltimore MD 21218

J. Davy Kirkpatrick
JPL/IPAC Caltech, MS 100-22, Pasadena CA 91125


A near infrared survey designed to detect widely separated, very low mass companions to M dwarfs within 8 pc stars is described. This survey is unique in that it is sensitive to companions with separations of ~100-1400 AU from primaries and with masses down to the 0.03 M level, thereby sampling rarely explored parameter space. In Phase I of this program, described here, candidate stellar and brown dwarf companions are identified by creating color magnitude plots of all detected point sources in the fields surrounding primaries and searching for objects that are bright enough to be stellar (M 11) or that fall close to theoretical brown dwarf isochrones like GD 165B (M 13). Common proper motion and spectroscopic checks are used to screen candidates. To date, all candidates for which we have made follow-up observations have been identified as background sources and no new low mass stellar or brown dwarf candidates have emerged from this survey. Phase II of this program will include a search for common proper motion between primaries and all field objects to M 17.5, allowing identification of widely separated substellar components, including objects like GL 229B.

Appears in the Astronomical Journal, volume 112.

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Ruth A. Kneale / / November 15, 1996