Imagine the Universe!
Imagine Home | Science | Advanced Science | 

Determining orbits and masses of binary stars

Much of the information we have about X-ray binaries has come from the study of X-ray pulsars. X-ray pulsars allow the determination of the orbital parameters of the binary system by the Doppler delays of the pulse arrival times. If the Doppler velocity curve of the primary is also available, the mass of the secondary star can be determined. This is how we know that the secondary must be a neutron star or black hole - all of the masses that have been determined are consistent with ~1.4 solar mass neutron stars or with higher mass black holes.

Last Modified: January 2011

If words seem to be missing from the articles, please read this.

Imagine the Universe! is a service of the High Energy Astrophysics Science Archive Research Center (HEASARC), Dr. Alan Smale (Director), within the Astrophysics Science Division (ASD) at NASA's Goddard Space Flight Center.

The Imagine Team
Project Leader: Dr. Barbara Mattson
Curator: Meredith Gibb
Responsible NASA Official: Phil Newman
All material on this site has been created and updated between 1997-2014.
This page last updated: Friday, 14-Jan-2011 15:02:48 EST