Could the Hercules satellite be a stellar stream in the Milky Way halo?
  We investigate the possibility that Hercules, a recently discovered Milky Way
(MW) satellite, is a stellar stream in the process of formation. This
hypothesis is motivated by Hercules' highly elongated shape as well as the
measurement of a tentative radial velocity gradient along its body. The
application of simple analytical techniques on radial velocity data of its
member stars provides tight constraints on the tangential velocity of the
system (v_t = -16^{+6}_{-22} km/s, relative to the Galactic Standard of Rest).
Combining this with its large receding velocity (145 km/s) and distance (138
kpc) yields an orbit that would have taken Hercules to within 6^{+9}_{-2} kpc
of the Galactic centre approximately 0.6 Gyr ago. This very small
perigalacticon can naturally explain the violent tidal destruction of the dwarf
galaxy in the MW's gravitational potential, inducing its transformation into a
stellar stream.
