WBVR Photometry of the CBS HZ Her/Her X-1

TL;DR

This study presents ten years of four-color photometry of the HZ Her/Her X-1 binary system, analyzing its long-term behavior and refining models of mass transfer to the neutron star's accretion disk.

Contribution

It provides detailed long-term photometric data and refines understanding of photometric effects related to mass transfer in the system.

Findings

Refined photometric effects on light curves.

Insights into mass transfer processes.

Long-term stability observed in the system.

Abstract

We report four-color WBVR photoelectric photometry of the close binary system (CBS) HZ HER/HER X-1 made in 1986-1994. Our photometry usually covered at least two 35d precession periods during each of the 1986-1990, 1992, and 1994 observing seasons. The accuracy and duration of our 10-year long photoelectric observations of the star with an x-ray source made it possible to study its long-term behavior. We refine some of the "fine" photometric effects on the light curves of the CBS and try to interpret them in terms of the model of mass transfer from the optical component of the CBS to the accretion disk (AD) of the neutron star (NS).