Periodic timing residuals in pulsating binary X-ray sources and orbital precession in Hercules X-1.
Abstract
Intrinsic variations of pulse frequency and reflection of pulses produce systematic residuals in pulse arrival times from pulsating binary X-ray sources. An iterative technique is used to calculate higher-order terms in the arrival-time curve of a variable-frequency binary source. A general framework is also formulated for studying time delays caused by reflection of pulses. By applying these methods to Her X-1, it is found that reflection effects and variations in pulse frequency due to accretion torques, stellar wobble, and changes in pulse shape can mimic the effects of orbital precession with the 35-day period. Observational tests are suggested to resolve this ambiguity in the interpretation of the timing data.
- Publication:
-
The Astrophysical Journal
- Pub Date:
- June 1978
- DOI:
- 10.1086/182704
- Bibcode:
- 1978ApJ...222L.113A
- Keywords:
-
- Binary Stars;
- Precession;
- Pulsars;
- Stellar Motions;
- X Ray Sources;
- Periodic Variations;
- Stellar Mass Accretion;
- Time Lag;
- X Ray Stars;
- Astronomy;
- Binaries:X-Ray Pulsars;
- Orbits:X-Ray Binaries