%0 Journal Article %T Discovery of an ultra-cool subdwarf: LSR1425+7102, first star with spectral type sdM8.0 %A Sebastien Lepine %A Michael M. Shara %A R. Michael Rich %J Physics %D 2003 %I arXiv %R 10.1086/374210 %X We report the discovery of the coolest subdwarf reported to date. The star LSR1425+7102 was discovered in our survey for faint high proper motion stars in the northern sky. Follow-up spectroscopy revealed the star to be a very red object with the characteristic signature of M subdwarfs: strong CaH bands but relatively weaker TiO bands. The CaH molecular band at $\approx\lambda$6900\AA\ is particularly strong. By extrapolating the empirical relationship between the strength of the CaH molecular band and the subdwarf subtype, we conclude that LSR1425+7102 is the first star to be discovered with spectral type sdM8.0. %U http://arxiv.org/abs/astro-ph/0301375v1