Uhuru observations of Hercules X-1This light curve of Her X-1 shows long term and medium term variability. Each pair of vertical lines deliniate the eclipse of the compact object behind its companion star. In this case, the companion is a 2 Solar-mass star with a radius of nearly 4 times that of our Sun. This eclipse shows us the orbital period of the system, 1.7 days. The long term variability shown here is precession of a disk of accreting matter around the neutron star. This precession has a 35-day period. In addition, the neutron star in Her X-1 is also a pulsar with a 1.24 second pulse period.
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HEASARC Home | Observatories | Archive | Calibration | Software | Tools | Students/Teachers/Public Last modified: Thursday, 26-Jun-2003 13:48:45 EDT HEASARC Staff Scientist Position - Applications are now being accepted for a Staff Scientist with significant experience and interest in the technical aspects of astrophysics research, to work in the High Energy Astrophysics Science Archive Research Center (HEASARC) at NASA Goddard Space Flight Center (GSFC) in Greenbelt, MD. Refer to the AAS Job register for full details. |