[Previous] | [Session 61] | [Next]
M. R. McGovern, I. S. McLean, L. Prato, A. Burgasser (UCLA), J. D. Kirkpatrick (IPAC)
The major goal of the NIRSPEC Brown Dwarf Spectroscopic Survey (BDSS - McLean et al. 2000, ApJ, 533, L45) is to obtain a complete sample of low resolution (R~2000) spectra spanning the M, L, and T dwarf sub-classes in order to extend spectral classification schemes to near-infrared wavebands and to investigate the spectral signatures of temperature, gravity, and composition by comparison to theoretical models. Additional goals include the acquisition of higher resolution spectra (R~25,000) of a sub-sample of the survey for detailed comparison with models and to search for radial velocity variations. Our approach is to observe two objects per sub-class at J-band at low resolution, with one object per sub-class observed from 0.9-2.5 microns to produce a complete, flux-calibrated spectrum overlapping with previously obtained Keck LRIS data from 0.5-1.0 microns. Several of the brighter sources have also been observed at high resolution at J-band. To date, over 50 objects have been studied including 7 M dwarfs, 30 L dwarfs and 15 T dwarfs. Correlations of the strength of spectral features with spectral type are shown. We also report on the probable identification of weak methane features in the K-band spectra of L7 and L8 dwarfs.
The author(s) of this abstract have provided an email address for comments about the abstract: mcgovern@astro.ucla.edu