INFRARED-SPECTRA OF LOW-MASS STARS - TOWARD A TEMPERATURE SCALE FOR RED DWARFS

We present new low-resolution (R similar to 250) 1.0-2.4 mu m spectra for 13 red dwarf stars. The sample size is increased to 16 by includin g other published infrared spectra. New, as well as published, red spe ctra are presented for 10 of these 16 stars, and new and published VRI JHKLL' photometry is also presented. Both halo and disk stars are incl uded in the sample, which covers a range of spectral type from dM0 to dM6.5. We derive bolometric luminosities and bolometric corrections fr om the observational data, finding good agreement with earlier results for the disk stars. We fit synthetic spectra generated by Allard & Ha uschildt's state-of-the-art model atmospheres to the observed spectra. Although some discrepancies remain between the theoretical and observ ed spectra, we find that the molecular features give a consistent valu e for effective temperature across the entire observed wavelength rang e. The T-eff values and radii derived, and their dependency on metalli city, are in agreement with the most recent structural models of low-m ass stars, removing the long-standing discrepancy between the observed and calculated locations of such stars in the H-R diagram, at least f or stars more massive than 0.1 M..