The Keplerian orbit of G2
  We give an update of the observations and analysis of G2 - the gaseous red
emission-line object that is on a very eccentric orbit around the Galaxy's
central black hole and predicted to come within 2400 Rs in early 2014. During
2013, the laser guide star adaptive optics systems on the W. M. Keck I and II
telescopes were used to obtain three epochs of spectroscopy and imaging at the
highest spatial resolution currently possible in the near-IR. The updated
orbital solution derived from radial velocities in addition to Br-Gamma line
astrometry is consistent with our earlier estimates. Strikingly, even ~6 months
before pericenter passage there is no perceptible deviation from a Keplerian
orbit. We furthermore show that a proposed "tail" of G2 is likely not
associated with it but is rather an independent gas structure. We also show
that G2 does not seem to be unique, since several red emission-line objects can
be found in the central arcsecond. Taken together, it seems more likely that G2
is ultimately stellar in nature, although there is clearly gas associated with
it.
