Not Your Grandmother's HII Regions: An X-ray Tour of Massive Star- forming Regions
Leisa Townsley, Penn State
Abstract:
The Chandra X-ray Observatory is providing remarkable new views of
massive star-forming regions, revealing all stages in the life cycle
of high-mass stars and their effects on their surroundings. We will
tour several such regions, highlighting physical processes that
characterize the life of a cluster of massive stars, from deeply- embedded cores too young to have established an HII region to
superbubbles so large that they shape our views of galaxies. Along
the way we see that X-ray observations reveal hundreds of pre-main
sequence stars accompanying the massive stars that power great HII
region complexes. The most massive stars themselves are often
anomalously hard X-ray emitters; this may be a new indicator of close
binarity or strong magnetic fields. These complexes are sometimes
suffused by diffuse X-ray structures, signatures of multi-million- degree plasmas created by fast O-star winds. In older regions we see
the X-ray remains of the deaths of massive stars that stayed close to
their birthplaces, exploding as cavity supernovae within the
superbubbles that these clusters created.