Photometric and Spectroscopic Analysis of Cool White Dwarfs with Trigonometric Parallax Measurements

A detailed photometric and spectroscopic analysis of cool (Teff < ∼ 12, 000 K) white dwarf stars is presented. The sample has been drawn from the Yale Parallax Catalog and from a proper-motion survey in the southern hemisphere. Optical BV RI and infrared JHK photometry, as well as spectroscopy at Hα, have been secured for a sample of 152 white dwarfs. The discovery of seven new DA white dwarfs, two new DQ white dwarfs, one new magnetic white dwarf, and three weak magnetic white dwarf candidates, is reported. Our sample also identifies 19 known or suspected double degenerates. Based partially on data obtained with the UK Infrared Telescope operated by the Joint Astronomy Centre, Hilo, HI, on behalf of the UK Particle Physics and Astronomy Research Council, and with the NASA Infrared Telescope Facility operated by the Institute for Astronomy at the University of Hawaii under contract to NASA. Visiting Astronomer, Cerro-Tololo Inter-American Observatory, National Optical Astronomical Observatories, which is operated by AURA, Inc., under contract with the National Science Foundation. Guest observer, Kitt Peak National Observatory, National Optical Astronomy Observatories, operated by the Association of Universities for Research in Astronomy, Inc., under cooperative agreement with the National Science Foundation. Visiting Astronomer at La Silla (ESO).