The following document lists the file abstract/MCOE_MALCOE02.abs
from catalogue VI/111.
A plain copy of the file
(without headers/trailers) may be downloaded.
High Mass X-ray Binary systems are a class of accreting binary that consist of an early type star (O or B) that is orbiting with a compact object, typically a neutron star. This proposal is concerned with the types of HMXB containing Be or Supergiant stars - an early type emission star that is orbiting with a neutron star. These systems exhibit transient bursts of X-ray emission. Sometimes on a regular basis corresponding to the periastron passage of the neutron star giving rise to accretion of circumstellar or stellar wind material onto the surface of the neutron star. However, the mechanism for this accretion is still not certain. In particular, it is not known whether an accretion disc is present during the accretion phase, or if it is only present for some of the time, or if matter accretes directly onto the neutron star without a disc being present. One of the critical factors influencing the creation of an accretion disc is the condition of the material being accreted, in particular the velocity of the material relative to the neutron star. This affects the ability of the neutron star to capture material flowing past it, and hence its ability to form an accretion disc. The aim of this proposal is to observe such systems while they are undergoing an X-ray outburst and hence they should have an unusually active and large circumstellar disk. We wish to obtain infrared line data from the circumstellar disc/wind to use as a diagnostic of conditions in the disc. This will then be combined with simultaneous X-ray observations of the system obtained with CGRO, in an attempt to determine what modes of accretion are taking place on to the neutron star. We will be able to detect within one day if any of our systems go into an active phase and alert ISO accordingly.