A
“Lithium Test” and Modeling of Lithium Lines
in Late-Type M Dwarfs: Teide1
Ya. V. Pavlenko
Main
Astronomical Observatory, Ukrainian Academy of Sciences, Kiev-22,
252650 Ukraine
Received September
23, 1996
Abstract—The
results of numerical modeling of lithium lines in the spectra of
late-type M dwarfs are discussed. “Line-by-line” and
“just-overlapping” approximations are used to compute
the molecular opacities. Synthetic spectra are computed near two
lithium lines—a resonance line at 
6708
and a subordinate line at 8126—for
a number of late-type M dwarfs using the model atmosphere grids
of Allard and Hauschildt. Thetwo molecular absorption models used
yield very similar profiles for strong lithium lines that could
in principle be observed in the spectra of brown dwarfs.
“Pseudoequivalent” widths of lithium absorption lines
are computed and compared with the equivalent widths in the
spectrum of the brown dwarf candidate Teide1 measured by Rebolo
et al. This comparison indicates that the lithium abundance
in Teide1’s atmosphere is high: 
> 3.0 and 
= 2.9 for 6708
and 8126, respectively. This provides strong
evidence for identification of Teide1 as a brown dwarf.
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