Formation of the optical spectra of the coolest M- and L-dwarfs and lithium abundances in their atmospheres

dc.creatorPavlenko, Ya. V.
dc.date2000-02-07
dc.date.accessioned2026-07-25T11:00:04Z
dc.descriptionTheoretical aspects of modeling of spectra of late M- and L-dwarfs are discussed. We show, that the processes of formation of spectra of M- and L-dwarfs are basically different. Instead of the case of M-dwarfs, atoms of Ti and V should be depleted into grains in the atmospheres of L-dwarfs. Overall shape of the L-dwarf spectra is governed by the K I + Na I resonance line wings of the huge strength. To fit lithium lines observed in spectra of the coolest dwarfs we used two additional suggestions: a) there are some EXTRA depletions of molecular species absorbed in the optical spectra of L-dwarfs; b) there may be (a few?) additional (``dusty''?) opacity sources in their atmospheres. Problems of lithium line formation and the ``natural'' limitation of their use for the ``lithium test'' for the case of L-dwarfs are considered.
dc.description6 pages, latex, 4 EPS figs, summary of talk at IAU Symposium 198: The Light Elements and their Evolution (Natal), ASP Conf. Series, 2000, eds. L. da Silva, M. Spite, and J.R. de Medeiros
dc.identifierhttps://arxiv.org/abs/astro-ph/0002144
dc.identifierhttp://arxiv.org/abs/astro-ph/0002144
dc.identifier.urihttps://dspace.dare.co.zw/handle/123456789/487
dc.subjectAstrophysics
dc.titleFormation of the optical spectra of the coolest M- and L-dwarfs and lithium abundances in their atmospheres
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