Misc,
X-ray Binaries
(Jan 25, 2017)
Abstract
This chapter discusses the implications of X-ray binaries on our knowledge of
Type Ibc and Type II supernovae. X-ray binaries contain accreting neutron stars
and stellar--mass black holes which are the end points of massive star
evolution. Studying these remnants thus provides clues to understanding the
evolutionary processes that lead to their formation. We focus here on the
distributions of dynamical masses, space velocities and chemical anomalies of
their companion stars. These three observational features provide unique
information on the physics of core collapse and supernovae explosions within
interacting binary systems. There is suggestive evidence for a gap between \~2-5
Msun in the observed mass distribution. This might be related to the physics of
the supernova explosions although selections effects and possible systematics
may be important. The difference between neutron star mass measurements in
low-mass X-ray binaries (LMXBs) and pulsar masses in high-mass X-ray binaries
(HMXBs) reflect their different accretion histories, with the latter presenting
values close to birth masses. On the other hand, black holes in LMXBs appear to
be limited to <\~12 Msun because of strong mass-loss during the wind Wolf-Rayet
phase. Detailed studies of a limited sample of black-hole X-ray binaries
suggest that the more massive black holes have a lower space velocity, which
could be explained if they formed through direct collapse. Conversely, the
formation of low-mass black holes through a supernova explosion implies that
large escape velocities are possible through ensuing natal and/or Blaauw kicks.
Finally, chemical abundance studies of the companion stars in seven X-ray
binaries indicate they are metal-rich (all except GRO J1655-40) and possess
large peculiar abundances of alpha-elements (Abridged)
