¥ There is a
relatively wide variety of line profile morphologies seen in Chandra and XMM observations of OB
stars, indicating that a surprising variety of high-energy physical processes
are occurring in early-type stars
¥ Supergiants
with massive radiation-driven winds have X-ray emitting plasma distributed throughout their winds:
Standard wind-shock models explain the data if the mean optical
depth of the cool wind component is several times lower than
expected (mass-loss rates overestimated? clumping?)
¥ Young O and
early B stars are well explained by the hybrid magnetically channeled wind shock model
¥ Maybe some
unusual objects like the Be star g Cas
have magnetic dynamos, perhaps due to star-disk interactions
¥ Normal B
stars donÕt fit neatly into any of these paradigms