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Paper: Confirmation and Characterization of Young Disk-Bearing Brown Dwarfs and sub-Brown Dwarfs
Volume: 448, 16th Cambridge Workshop on Cool Stars, Stellar Systems, and the Sun
Page: 633
Authors: Gully-Santiago, M. A.; Allers, K. N.; Jaffe, D. T.
Abstract: The lowest mass objects in nearby star forming regions now accessible to spectroscopy are in the sub-brown dwarf regime, with estimated masses comparable to the masses of extrasolar planets and bordering the threshold of opacity limited fragmentation. We confirm and characterize, using R∼ 1500 near-infrared spectroscopy, 17 candidate young substellar objects in the Ophiuchus, Lupus I, and Chamaeleon II star forming regions from the Allers et al. (2006) sample. The spectral types range from M2-L2.5, with extinctions of 0 < AV < 10. We assign youth based on the presence of mid-IR excess and gravity sensitive spectral indices, like the triangular H–band continuum shape and the Na I equivalent width. All but one source from the photometrically selected sample of 19 are confirmed as bona fide young late type objects, an exceptional confirmation rate for this type of study. Two of the sources are known wide-separation binaries. We explore the advantage of increased resolution over existing low resolution spectroscopy for six objects. The objects' derived luminosities are in the range –3.3< log L/L<–0.6, placing the lowest luminosity candidates comfortably in the substellar or even sub brown-dwarf mass regime.
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