Optical pulsations from HZ Herculis/Hercules X-1: the self-consistent 35 day picture

Journal Article · Thu Dec 01 04:00:00 EST 1983 · Astrophys. J.; (United States)

DOI:https://doi.org/10.1086/161532· OSTI ID:5926058

Middleditch, J

A detailed analysis of the optical pulsation data from HZ Her shows that all of the 35 day characteristics can be interpreted in the light of episodic mass transfer every 0.81 days lasting at least 4 hr and obscuration by a tilted accretion disk which undergoes one cycle of retrograde progression every approx. 35 days. The predominant systematic shifts of the optical pulsation velocities can be related to the x-ray shadowing of the phi/sub 1/d/sub 7/ = 0.75 side of the lobe of HZ Her by the mass transfer stream and the associated disk rim structure. In the context of this new understanding of the 35 day effects, the pulsation data strongly affirm the assumptions of prograde spin for Her X-1, and aligned corotation and Roche lobe filling for HZ Her. Consideration of the accurately measured x-ray eclipse duration and the minimum orbital co-inclination required to produce the observed 35 day optical and x-ray variability may limit the Her X-1 mass to less than 1.4 mass of sun. A good model atmosphere for the optical pulsations could reduce the Her X-1 mass error to less than 0.10 Mass of sun.

• Research Organization: Los Alamos National Lab., NM
• OSTI ID: 5926058
• Journal Information: Astrophys. J.; (United States), Journal Name: Astrophys. J.; (United States) Vol. 275; ISSN ASJOA
• Country of Publication: United States
• Language: English

Related Subjects

640103* -- Astrophysics & Cosmology-- Quasi-Stellar
Radio
& X-Ray Sources-- (-1987)
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
ACCRETION DISKS
ATMOSPHERES
BINARY STARS
COSMIC RADIO SOURCES
COSMIC RAY SOURCES
COSMIC X-RAY SOURCES
ECLIPSE
ELECTROMAGNETIC RADIATION
IONIZING RADIATIONS
MASS
MASS TRANSFER
MOTION
PULSARS
PULSATIONS
RADIATIONS
ROCHE EQUIPOTENTIALS
ROTATION
STARS
STELLAR ATMOSPHERES
VARIATIONS
VELOCITY
VISIBLE RADIATION
X RADIATION