Bibcode
Manjavacas, E.; Goldman, B.; Alcalá, J. M.; Zapatero-Osorio, M. R.; Béjar, V. J. S.; Homeier, D.; Bonnefoy, M.; Smart, R. L.; Henning, T.; Allard, F.
Referencia bibliográfica
Highlights of Spanish Astrophysics VIII, Proceedings of the XI Scientific Meeting of the Spanish Astronomical Society held on September 8-12, 2014, in Teruel, Spain, ISBN 978-84-606-8760-3. A. J. Cenarro, F. Figueras, C. Hernández-Monteagudo, J. Trujillo Bueno, and L. Valdivielso (eds.), p. 500-505
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5
2015
Número de citas
0
Número de citas referidas
0
Descripción
The refinement of the brown dwarf binary fraction may contribute to the
understanding of the substellar formation mechanisms. Peculiar brown
dwarf spectra or discrepancy between optical and near-infrared spectral
type classification of brown dwarfs may indicate unresolved brown dwarf
binary systems. We obtained medium-resolution spectra of 22 brown dwarfs
of potential binary candidates using X-Shooter at the VLT. We aimed to
select brown dwarf binary candidates. We also tested whether BT-Settl
2014 atmospheric models reproduce the physics in the atmospheres of
these objects. To find different spectral type spectral binaries, we
used spectral indices and we compared the selected candidates to single
spectra and composition of two single spectra from libraries, to try to
reproduce our X-Shooter spectra. We also created artificial binaries
within the same spectral class, and we tried to find them using the same
method as for brown dwarf binaries with different spectral types. We
compared our spectra to the BT-Settl models 2014. We selected six
possible candidates to be combination of L plus T brown dwarfs. All
candidates, except one, are better reproduced by a combination of two
single brown dwarf spectra than by a single spectrum. The one-sided
F-test discarded this object as a binary candidate. We found that we are
not able to find the artificial binaries with components of the same
spectral type using the same method used for L plus T brown dwarfs. Best
matches to models gave a range of effective temperatures between 950 K
and 1900 K, a range of gravities between 4.0 and 5.5. Some best matches
corresponded to supersolar metallicity.