  Infrared surveys have discovered a significant population of bright (K<19)
extremely red (R-K>6) objects. Little is known about the properties of these
objects on account of their optical faintness (R>24). Here, we report deep
infrared imaging and spectroscopy of one of the extremely red objects (EROs)
discovered by Hu \& Ridgway (1994) in the field of the z=3.79 quasar
PC1643+4631A. The infrared images were obtained in 0.5" seeing, and show that
the object (denoted HR10) is not a dynamically relaxed elliptical galaxy
dominated by an old stellar population as was previously suspected, but instead
has an asymmetric morphology suggestive of either a disk or an interacting
system. The infrared spectrum of HR10 shows a single, possibly broad emission
feature at 1.60um which we identify as Halpha+[NII] at z=1.44. The luminosity
and width of this emission line indicates either intense star formation (about
20h^{-2} solar masses/yr) or the presence of an active nucleus. Based on the
rest frame UV-optical spectral energy distribution, the luminosity of HR10 is
estimated to be 3 to 8 L*. The colors of HR10 are unusually red for a galaxy
(at z=1.44 the age of HR10 is at most 2 to 8 Gyr depending on cosmology), and
indicate that HR10 is dusty. HR10 is detected weakly at radio wavelengths; this
is consistent with either the starburst or AGN hypothesis. If HR10 is a typical
representative of its class, EROs are numerous and represent a significant
component of the luminous objects in the Universe at z approx 1.5.
