Three newly recognized dwarf carbon stars

Abstract

We confirm the identification of two faint high-latitude carbon stars with previously cataloged high proper motion objects, and report the discovery of proper motion in a third. The R = 15.5 star CLS 96 corresponds to LP 328-57, with μ = 0″.28 yr -1 , and C*22 (Bothun et al.) is LP 765-18 = LHS 1075, with R = 14 and μ = 0″.62 yr -1 . In addition, CLS 31, with R = 16.5, is found to have μ = 0″.13 yr -1 . These three objects are thus inferred to be dwarf carbon stars, supplementing the one previously known case. All of these objects have JHK colors similar to the prototype dwarf C star, G77-61, suggesting IR colors as a useful luminosity indicator LP 328-57 and G77-61 also share certain spectral peculiarities. Both LP 328-57 and LHS 1075 are probably at distances of ∼ 100 pc and may have detectable parallaxes. The past assumption made by several groups (ourselves included) that faint high-latitude C stars are in the distant halo, and thus useful dynamic probes, is obviously incorrect for some yet-to-be-determined fraction of these objects.