K-band spectra and narrowband photometry of denis field brown dwarfs

Infrared spectra at 1.9-2.5 micron and narrowband photometry of three low-mass objects, DENIS-P J0205.4-1159, J1058.7-1547, and J1228.2-1547, are presented. As shown previously by Delfosse et al. (1997, AA, 327, L25), DENIS-P J0205.4-1159 shows an absorption feature at 2.2 microns. We attribute this absorption to H_2. A simple two-parameter analysis of the K-band spectrum of low-mass objects is presented in which the relative strength of the H_2O and H_2 absorption bands is found to be correlated with the effective temperature of the objects. The analysis confirms that DENIS-P J0205.4-1159 is the lowest-temperature object of the three. We present narrow-band photometry of these objects which provides the continuum flux level inbetween the deep H_2O absorption bands. These data show the continuum level accurately for the first time, and they will provide tight constraints for spectral models of these interesting objects.

STARS LOW-MASS

References(8)

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The near-infrared spectrum of the brown dwarf gliese 229b

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