Theoretical calculations of the optical pulsation from HZ Herculis

Abstract

view Abstract Citations (16) References (35) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS Theoretical calculations of the optical pulsation from HZ Herculis. Chester, T. J. Abstract A formalism is presented that enables one to calculate the amount of pulsed optical radiation emergent from a stellar atmosphere exposed to pulsed X-rays. The formalism takes account of the time evolution of the X-ray energy deposited in a time-independent atmosphere. For HZ Her, the calculated optical pulsation agrees with the observed amplitude. For fixed system parameters, allowable nonuniform X-ray beams can cause the amplitude of the optical pulsation to vary by a factor of 2 and can shift the frequency of the pulsation, and hence the inferred optical velocity. The presence of soft X-rays (0.1-1 keV) can significantly affect the calculated pulsation amplitude. This dependence constrains any possible soft X-ray flux that may fall on the surface of HZ Her. The assumption of corotation along with limits from the optical pulsation data give a mass range of about 0.8-1.6 solar masses for Her X-1. If the light curve observed during the extended lows of HZ Her is due to ellipsoidal variation, this range may be further restricted. Publication: The Astrophysical Journal Pub Date: June 1978 DOI: 10.1086/156183 Bibcode: 1978ApJ...222..652C Keywords: Binary Stars; Stellar Atmospheres; Stellar Mass; X Ray Sources; Albedo; Atmospheric Models; Light Emission; Periodic Variations; Astrophysics; X-Ray Sources:Optical Variations full text sources ADS | data products SIMBAD (1)