  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.
