Three Newly Discovered M‐Dwarf Companions of Solar Neighborhood Stars11Portions of the data presented here were obtained at the W. M. Keck Observatory, which is operated as a scientific partnership among the California Institute of Technology, the University of California, and the National Aeronautics and Space Administration. The Observatory was made possible by the generous financial support of the W. M.

Abstract

ABSTRACTWe present low‐resolution spectroscopy of newly discovered candidate companions to three stars in the solar neighborhood. All three companions are M dwarfs, with spectral types ranging from M4 to M9.5. In two cases, G85‐55B (M6) and G87‐9B (M4), we have circumstantial evidence from spectroscopy, photometry, and limited astrometry that the systems are physical binaries; in the third, G216‐7B (M9.5), comparison of POSS II IIIaF plate material and the 2MASS image indicates common proper motion. The primary star in this system, G216‐7A (M0), is itself an unresolved, nearly equal‐mass binary. All three low‐mass companions are highly likely to be stellar in nature, although G216‐7B lies very close to the hydrogen‐burning limit.