  We measured the near-infrared orbital light curve of the black hole binary
A0620-00 in 1995 and 1996. The light curves show an asymmetric, double-humped
modulation with extra emission in the peak at orbital phase 0.75. There were no
significant changes in the shape of the light curve over the one-year
observation period. There were no sharp dips in the light curves nor reversals
of the asymmetry between the two peaks as seen in earlier observations. The
light curves are well fit by models incorporating ellipsoidal variations from
the mass-losing K-type star plus a beamed bright spot on the accretion disk
around the compact star. The long-term stability of the light curve shape rules
out superhumps and star spots as sources of asymmetry when we observed
A0620-00. The ellipsoidal variations yield a lower limit i >= 38 deg on the
orbital inclination. The light curves show no eclipse features, which places an
upper limit i <= 75 deg. This range of inclinations constrains the mass of the
compact object to 3.3 < M_1 < 13.6 Msun. The light curves do not further
constrain the orbital inclination because the contribution of the accretion
disk to the observed flux is unknown. We argue that a previous attempt to
measure the near-infrared flux from the accretion disk using the dilution of
the 12CO(2,0) bandhead in the spectrum of the K star is not reliable because
the band strength depends strongly on surface gravity.
