Name/Affiliation: John Subasavage (U. S. Naval Observatory)
A UCAC4 Trawl for New Nearby Red Dwarfs
We present 16 photometric color-Mk relations using the U. S. Naval Observatory fourth CCD Astrograph Catalog (UCAC4). These relations estimate distances to nearby red dwarfs at the 15% accuracy level using photometry from the Two-Micron All-Sky Survey (2MASS) and the AAVSO Photometric All-Sky Survey (APASS). A sample of nearby stars from the Research Consortium On Nearby Stars (RECONS) group along with a supplemental list of very red stars all having accurate trigonometric parallaxes are used to generate the relations. Color, proper motion, and existing literature sources are used in an attempt to attain a clean sample of red dwarfs while limiting the amount of contamination from background giants. From this sample, we find 1775 candidate nearby M-dwarfs estimated to be within 25 pc. Of this sample, 338 have no previously known published parallax or distance estimate and five of these are estimated to be within 10 pc. The nearest distance estimate of 5.93 pc was found for a star with a V magnitude of 10.5. This and other discoveries during this effort suggest that yet more nearby stars remain undiscovered, even at relatively bright magnitudes.