Hercules and Wolf 630 Stellar Streams and Galactic Bar Kinematics
  We have identified the four most significant features in the UV velocity
distribution of solar neighborhood stars: H1, H2 in the Hercules stream and W1,
W2 in the Wolf 630 stream. We have formulated the problem of determining
several characteristics of the central Galactic bar independently from each of
the identified features by assuming that the Hercules and Wolf 630 streams are
of a bar-induced dynamical nature. The problem has been solved by constructing
2:1 resonant orbits in the rotating bar frame for each star in these streams.
Analysis of the resonant orbits found has shown that the bar pattern speed is
45-55 km/s/kpc, while the bar angle lies within the range 40-60 degrees. The
results obtained are consistent with the view that the Hercules and Wolf 630
streams could be formed by a long-term influence of the Galactic bar leading to
a characteristic bimodal splitting of the UV velocity plane.
