منابع مشابه
Near-Infrared Spectral Classification of late-M and L Dwarfs
We present near-infrared (1 to 2.5 μm) low-resolution spectroscopy of eleven ultracool dwarfs with spectral types ranging from M7 to L8. Combining our observations with data published previously by Leggett et al. (2001), we have measured equivalent widths for the strongest atomic features and constructed narrowband indices to gauge the strength of the strongest molecular features. Those measure...
متن کاملA Unified Near-infrared Spectral Classification Scheme for T Dwarfs
A revised near-infrared classification scheme for T dwarfs is presented, based on and superseding prior schemes developed by Burgasser and coworkers and Geballe and coworkers, and defined following the precepts of the MK process. Drawing from two large spectroscopic libraries of T dwarfs identified largely in the SloanDigital Sky Survey and the Two Micron All Sky Survey, nine primary spectral s...
متن کاملInfrared Spectra and Spectral Energy Distributions of Late–M– and L–Dwarfs
We have obtained 1.0—2.5μm spectra at R∼600 of 14 disk dwarfs with spectral types M6 to L7. For four of the dwarfs we have also obtained infrared spectra at R∼3000 in several narrow intervals. In addition, we present new L′ photometry for four of the dwarfs in the sample, which allows improved determinations of their bolometric luminosities. While obtaining the photometry we resolved the L-dwar...
متن کاملSpectral Energy Distributions for Disk and Halo M – Dwarfs
We have obtained infrared (1—2.5µm) spectroscopy for 42 halo and disk dwarfs with spectral type M1 to M6.5. These data are compared to synthetic spectra generated by the latest model atmospheres of Allard & Hauschildt. Photospheric parameters metallicity, effective temperature and radius are determined for the sample. We find good agreement between observation and theory except for known proble...
متن کاملSpectral evidence for dust in late-type M dwarfs
We have found a dramatic change in the spectra of late-type M dwarfs at wavelengths shorter than 0.75μm. Comparisons with synthetic spectra illustrate that this change is well explained by the presence of dust. It thus seems that a substantial part of the long-standing discrepancies between late-type M dwarf models and observations arises from dust as recently proposed by Tsuji, Ohnaka & Aoki (...
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ژورنال
عنوان ژورنال: Monthly Notices of the Royal Astronomical Society
سال: 1994
ISSN: 0035-8711,1365-2966
DOI: 10.1093/mnras/267.2.413