Compact Radio Sources within 30" of Sgr A*: Proper Motions, Stellar
  Winds and the Accretion Rate onto Sgr A*
  Recent broad-band 34 and 44 GHz radio continuum observations of the Galactic
center have revealed 41 massive stars identified with near-IR counterparts, as
well as 44 proplyd candidates within 30" of Sgr A*. Radio observations obtained
in 2011 and 2014 have been used to derive proper motions of eight young stars
near Sgr A*. The accuracy of proper motion estimates based on near-IR
observations by Lu et al. and Paumard et al. have been investigated by using
their proper motions to predict the 2014 epoch positions of near-IR stars and
comparing the predicted positions with those of radio counterparts in the 2014
radio observations. Predicted positions from Lu et al. show an rms scatter of 6
mas relative to the radio positions, while those from Paumard et al. show rms
residuals of 20 mas, which is mainly due to uncertainties in the IR-based
proper motions. Under the assumption of homogeneous ionized winds, we also
determine the mass-loss rates of 11 radio stars, finding rates that are on
average $\sim$2 times smaller than those determined from model atmosphere
calculations and near-IR data. Clumpiness of ionized winds would reduce the
mass loss rate of WR and O stars by additional factors of 3 and 10,
respectively. One important implication of this is a reduction in the expected
mass accretion rate onto Sgr A* from stellar winds by nearly an order of
magnitude to a value of few$\times10^{-7}$ \msol\ yr$^{-1}$. Finally, we
present the positions of 318 compact 34.5 GHz radio sources within 30\arcs\ of
Sgr A*. At least 45 of these have stellar counterparts in the near-IR $K_s$
(2.18 $\mu$m) and $L'$ (3.8$\mu$m) bands.
