  Direct images of Betelgeuse were obtained over a span of 4 years with the
Faint Object Camera on the Hubble Space Telescope. These images reveal the
extended ultraviolet continuum emission (about 2 times the optical diameter),
the varying overall ultraviolet flux levels and a pattern of bright surface
continuum features that change in position and appearance over several months
or less. Concurrent photometry and radial velocity measures support the model
of a pulsating star, first discovered in the ultraviolet from IUE. Spatially
resolved HST spectroscopy reveals a larger extention in chromospheric emissions
of Mg II as well as the rotation of the supergiant. Changing localized subsonic
flows occur in the low chromosphere that can cover a substantial fraction of
the stellar disk and may initiate the mass outflow.
