AST-9712013 Abstract - Morgan The stellar binaries that are X-ray binary consist of either a main-sequence star or post-main-sequence star (called the companion) and a compact object. The compact object is usually either a neutron star or a black hole, although sometimes it can be a white dwarf star. These binary systems emit X-ray light generated by material, released by the companion star, falling upon the compact object. These interesting objects were first detected in the X-ray region of the electromagnetic spectrum during the very first astronomical X-ray observations in 1962, which detected the low-mass X-ray binary system Scorpius X-l. Ever since then, astronomers have been trying to understand these systems. The interpretation of the observations of these objects can yield interesting answers into the nature of how stars evolve, the physical properties of stars, and the deaths of stars. The systems may be divided into two main classes: low-mass (LXRB) and high-mass (HXRB). The terms "low-mass" or "high-mass" refer to the mass of the companion star. In general, LXRB companions have masses greater than two solar masses. The Be/X-ray binaries, a certain type of HXRB, have masses between eight and fifteen solar masses. The X-ray binary stellar systems emit light in several spectral regions, including X-ray, optical, and infrared wavelengths. By the analysis of the data from the various spectral regions, and the relationships between the emissions from these regions, astronomers can better understand the nature of these stars and perhaps find clues to help astronomers find out more about the evolution of stars. There are only thirty known Be/X-ray binaries. A large percentage of the stars are in binary systems and several X-ray binary stellar systems may not have been discovered yet. The research plan to be carried out is designed to help the principal investigator better understand the underlying properties of Be/X-ray binary syst ems. During the research period supported by this award, the Principal Investigator (PI) will spend time educating himself in the subject through researching the scientific literature, meeting other researchers in the field (and eventually beginning collaborations with them), and analyzing archival data of X- ray binaries taken by several X-ray, optical, and infrared telescopes, including data from the satellites known as Rosat, Asca, and the Hubble Space Telescope (HST). The award will enable the PI, who has extensive experience with the X-ray data analysis of quasars (using data from the satellites IRAF/PROS and Xspec) , will easily move into the area of the study of X-ray binaries. This award will make it possible to determine if a more extensive project in the study of X-ray binary stellar systems is reasonable and feasible. This award is supported jointly by the Division of Astronomical Sciences and the Office of Multidisciplinary Activities in the Directorate for Mathematical and Physical Sciences at NSF.
