Abstract

Trigonometric parallaxes, CCD and IR photometry, and low-resolution spectroscopy of three cold white dwarfs (ER8, LHS 483, and LHS 378) and a dM8 red dwarf (LHS 3003) are presented and used to calculate their distances, luminosities, and bolometric corrections. Results clearly indicate a nonblack body shape of the energy distribution for the cold white dwarfs, this is very clear in the case of LHS 378 which shows a strong IR defficiency similar to LHS 1126.