2007/05/02 by I. Neill Reid, Kelle L. Cruz, Peter Allen +6 · 97 citations
Physics and Astronomy · #Astronomy #Astronomy and Astrophysical Research #Astrophysics #Astrophysics and Star Formation Studies #Galaxy #K-type main-sequence star #Luminosity #Luminosity function #Physics #Pleiades #Proper motion #ROSAT #Sky #Stars #Stellar classification #Stellar, planetary, and galactic studies #T Tauri star #astro-ph
paper · pdf · doi:10.1086/517914
published in The Astronomical Journal 133(6), 2825-2840 (Institute of Physics) · Accepted for publication by the Astronomical Journal
openalex publication_date 2007/05/02 · arxiv created 2008/06/20 · arxiv updated 2009/12/01 · openalex created_date 2016/06/24 · openalex updated_date 2026/08/05
We have combined near-infrared data from the Two Micron All Sky Survey with ancillary optical data to identify previously unrecognized proper-motion stars that have colors and magnitudes consistent with nearby M dwarfs. We present follow-up observations of 392 stars from that sample, including ∼200 stars discussed here for the first time. Our distance estimates, based primarily on spectroscopic parallaxes, place 123 stars within 20 pc of the Sun. One hundred and seventy-six stars exhibit Hα emission, and 82 stars have plausible X-ray counterparts from ROSAT observations. The distribution of chromospheric and coronal activity is broadly consistent with data for other nearby late-type stars, with ∼30 stars having activity levels comparable to Pleiades M dwarfs. We have identified several M dwarfs that are probably wide ( >1000 AU) companions of F and G stars. We have recomputed the 20 pc luminosity function, adding the 123 new candidates found in the present survey. The revised luminosity function is in closer agreement with the 8 pc data set for stars with M J > 8 but probably remains incomplete at the ∼20% level.