Spectroscopic Identification of White Dwarfs in the New Luyten Two-Tenths Survey

Abstract

We spectroscopically identify New Luyten Two-Tenths (NLTT) stars from the reduced proper-motion diagram of Salim & Gould. Five out of 16 objects investigated are identified as white dwarfs: four hydrogen-rich DA stars (NLTT 8581, NLTT 31748, NLTT 53177, and NLTT 56805) and one helium-rich (NLTT 8435). The properties of the stars are further constrained using Two Micron All Sky Survey photometric measurements and, in the case of NLTT 31748, using International Ultraviolet Explorer spectrophotometry. The distances range from 15 to 23 pc, and therefore the sample contributes to estimates of the local density of white dwarf stars. The newly found objects are kinematically consistent with a thick or old thin disk membership. We discuss the likelihood of further identifications. Show more