Newly identified cold subdwarfs - LHS 375, LHS 407, LHS 3181, and LHS 3555

Abstract

Four new cold subdwarfs have been identified from Luyten's LHS Catalog (1976), LHS 375, LHS 407, LHS 3181, and LHS 3555. CCD B, V, R, and I photometry; infrared J, H, and K photometry and spectra of the stars have been obtained. We discuss their location in different color-color diagrams. They suggest a subdwarf class, and are consistent with the strengths of their CaH bands with respect to TiO bands. We also obtained CCD trigonometric parallaxes indicating absolute visual magnitudes for them from 1.5 to 2 mag below the dwarf main sequence.