Abstract
Pulse-timing observations of the binary X-ray pulsars provide a means of determining the orbital parameters of these systems to high precision. The orbital parameters of about ten of the 24 presently known binary X-ray pulsars have been reliably determined, and of these, six have had optical radial velocities measured and show X-ray eclipses, allowing the complete orbital parameters, including the neutron star mass, to be determined (Joss and Rappaport, 1984). By making repeated orbital determinations over a period of years it is possible to search for changes in the orbital parameters, particularly the longitude of periastron (apsidal motion), and the orbital period. This type of measurement provides the only empirical information on the evolution of these systems. The study of the pulse period changes in these systems (due to accretion torques) does provide an additional timescale, but it is not directly related to the orbital dynamics or the properties of the companion stars (cf. Savonije, 1983; Henrichs, 1983).
Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
