Metal--Poor Stars at the Terminus of the Hydrogen--Burning Sequence
Session 43 -- Searching for Brown Dwarfs
Display presentation, Wednesday, 1, 1994, 9:20-6:30

## [43.02] Metal--Poor Stars at the Terminus of the Hydrogen--Burning Sequence

S.K. Leggett (UH Hilo, JAC Hawaii), G. Berriman (GSC, Laurel MD)

We present 1-2.4$\mu$m spectra of metal--poor very low--mass stars. The data are compared to similar spectra of metal--rich stars in an effort to distinguish between temperature and metallicity effects in the energy distributions of such stars. The stars cover a range in spectral type of about dM0 to dM5. The latter corresponds to the lower temperature (or mass) limit for hydrogen--burning for very metal--poor stars, as spectral types are based on the appearance of optical features, in particular the strength of the TiO bands. The data will be used to constrain new model atmospheres that are being calculated by other groups, increasing our understanding of, for example, the important opacity sources in the atmospheres of stars at the terminus of the main sequence. (This work was partially supported by NSF grant AST 93 15372.)