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Formation of the Optical Spectra of the Coolest M- and L-dwarfs and Lithium Abundances in their Atmospheres

Published online by Cambridge University Press:  25 May 2016

Yakiv V. Pavlenko
Yakiv V. Pavlenko*
Affiliation:
Main Astronomical Observatory of NAS, Golosiiv woods, 03680, Kyiv-127, Ukraine

Abstract

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Theoretical 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 VO 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 discussed.

Type
6. Stellar Knowledge to and from Light Elements
Information
Symposium - International Astronomical Union , Volume 198: The Light Elements and their Evolution , 2000 , pp. 454 - 459
Copyright
Copyright © Astronomical Society of the Pacific 2000 

References

Allard, F., Hauschildt, P.H. 1995 ApJ, 445, 433 Google Scholar
Burgasser, A. J., Kirkpatrick, J. D., Brown, M. E., et al. 1999, ApJ, 522, L65 Google Scholar
Basri, G., Martín, E. L., 1999. AJ, 118, 2460.CrossRefGoogle Scholar
Kirkpatrick, J. D., Reid, I. N., Liebert, J., et al. 1999, ApJ, 519, 802 Google Scholar
Magazzu, A., Martín, E. L., Rebolo, R. Ya. 1991, A&A, 249, 149.Google Scholar
Magazzu, A. Rebolo, R., Pavlenko, Ya. 1992, ApJ,Google Scholar
Martín, E. L., Basri, G., Delfosse, X., Forveille, T. 1997, A&A, 327, L29 Google Scholar
Oppenheimer, B., Basrii, G., Nakajima, T., Kulkarni, S.L. 1997, AJ, 113, 296.Google Scholar
Pavlenko, Ya.V. 1997, Ap&SS, 253, 43.Google Scholar
Pavlenko, Y. V. 1997a. Astron. Rept., 41, 537.Google Scholar
Pavlenko, Ya. V. 1998, Astron. Reports, 42, 787 Google Scholar
Pavlenko, Ya. V., Zapapero Ozorio, M.R., Rebolo, R. 2000, A&A, in press (astroph 0001060) Google Scholar
Pavlenko, Ya. V., Oppenheimer, B. 1988, ASP Conf. Ser. 154, 1768.Google Scholar
Pavlenko, Ya. V. 1998b, Atronom. Report, 42, 787.Google Scholar
Pavlenko, et al. Pavlenko, Ya. V., Rebolo, R., Martín, E. L., García López, G. 1995, A&A, 303, 807.Google Scholar
Plez, B. 1998, A&A, 337, 495.Google Scholar
Rebolo, R., Martín, E.L., Magazzu, A. 1992,Google Scholar
Rebolo, R., Martín, E.L., Magazzu, A. 1992, ApJ, 389, L83.Google Scholar
Rebolo, R., Martín, E.L., Basri, G., Marcy, G.W., And Zapatero, G.W. Osorio, M.R. 1996, ApJ, 469, L53.Google Scholar
Strauss, M. A., Fan, X., Gunn, J. E. et al. 1999, ApJ, 1999, 522, L61 Google Scholar
Tsuji, T. 1999a, in Low-Mass Stars and Brown Dwarfs in Stellar Clusters and Associations, La Palma, CUP, in press Google Scholar