Evidence for a 35 day precession in the orbit of Hercules X-1.
Abstract
If the binary orbital plane of Hercules X-1 precesses, the X-ray pulse arrival times from this source will display additional periodicities corresponding to sidebands of the precessional and orbital periods. A search of Uhuru data from the January and March 1972 on states of Her X-1 yields marginal evidence for precessional motion, with a periodic shift in pulse arrival time having an amplitude of about 0.03 sec and a period of approximately 1.6 days, which corresponds to a variation in orbital inclination having an angular amplitude of at least 1 deg of arc and a precessional period of approximately 35 days. This evidence lends support to a class of models wherein the 35-day on-off cycle of Her X-1 is due to variable obscuration by a wobbling accretion disk.
- Publication:
-
The Astrophysical Journal
- Pub Date:
- April 1977
- DOI:
- 10.1086/182409
- Bibcode:
- 1977ApJ...213L..57F
- Keywords:
-
- Binary Stars;
- Precession;
- Pulsars;
- Stellar Motions;
- X Ray Sources;
- X Ray Stars;
- Angular Momentum;
- Astronomical Models;
- Circular Orbits;
- Orbital Elements;
- Orbital Velocity;
- Pulsed Radiation;
- Uhuru Satellite;
- Astronomy