OPTICAL SPECTRA OF L - DWARFS

Ya. Pavlenko

Анотація


Theoretical spectra, of L-dwarfs (Teff <2200 K) were computed for a. grid of the "dusty" C-model atmospheres of Tsuji (1998). To fit the observed spectra of L-dwarfs we used two additional (evristic) suggestions:

  • molecular densities of TiO and VO governed the visible spectra, of M-dwarfs are reduced due to the extra depletion of V and Ti atoms into grains in atmospheres of Teff <2200 K;
  • There are (a few) additional opacity k sources in L-dwarf atmospheres; 

A few kinds of k = f(A) dependences were used to get "the better fit" of observed spectra of L-dwarfs, We show:

  • We may fit the observed sequence of L-dwarf spectra using in the frame of our simple model;
  • Observed sequence of the L-dwarf spectra is the temperature sequence; 
  • At first time, the region of 860 nm contained CrH bands is well fitted; 
  • There are a few possibilities to get the reliable fits to the observed spectra; 
  • In the frame of our approach we have found the solution even for the case of G1229B.

Ключові слова


Late brown dwarfs, stellar spectra, lithium abundances.

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Посилання


Pavlenko, Ya.V., Rebolo R., Martin E.L., Garcia Lopez R.J.: 1995. Astron. AStrophys, 3D8, 807

Pavlenko, Ya.V. 1998.: Astron. Reports, 42, 787

Pavlenko, Ya.V. 1999.: Astron. Reports, 43, accepted

Pavlenko Ya.V., Rebolo, R., Zapatero Osorio, M.R. 1998.: in Euroconference on "Low mass stars and brown dwarfs is stellar clusters and associations", Los-Cancajos, La Palma, Spain, May 11-15, in press.

Pavlenko Ya.V., Rebolo, R., Zapatero Osorio, M.R.: 1699, Astron. Astrophys., submitted.

Tsuji, T. 1998.: in Euroconference on "Low mass stars and brown dwarfs is stellar clusters and associations", Los-Cancajos, La Palma, Spain, May 11-15, in press.

Tsuji, T., Ohnaka, K., Aoki, W.: 1996a, Astron. Astrophys., 305, L1




DOI: https://doi.org/10.18524/1810-4215.1999.12.93177

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