• DOI:10.3847/1538-4357/ac496f
• Corpus ID: 245853832

The Evolution of the Orbital Lightcurve of Hercules X-1 with 35 Day Phase

@article{Wang2022TheEO,
  title={The Evolution of the Orbital Lightcurve of Hercules X-1 with 35 Day Phase},
  author={Yuyang Wang and Denis A. Leahy},
  journal={The Astrophysical Journal},
  year={2022},
  volume={927}
}

• Yuyang Wang, D. Leahy
• Published 11 January 2022
• Physics
• The Astrophysical Journal

Hercules X-1/HZ Hercules (Her X-1/HZ Her) is an X-ray binary monitored by multiple X-ray missions since the last century. With the abundance of long-term observations, we present a complete set of orbital lightcurves of Her X-1/HZ Her during the six states of the 35 day cycle in multiple energy bands. These illustrate in detail the changing lightcurve caused by the rotating twisted-tilted accretion disk surrounding the neutron star. The orbital lightcurves during the main high state are analyzed in 0.05 35 day phase intervals. These show the regular occurrence of pre-eclipse dips that march to earlier orbital phases as the 35 day phases increase. From the multiband lightcurves, we derive the time-average orbital phase dependence of column density for photoelectric absorption and energy-independent transmission as a function of 35 day phase. The X-ray lightcurves during low states are similar in shape to the optical low-state lightcurve, but X-ray leads optical by ≃0.04–0.08 in orbital phase.