Modelling of 35-d superorbital cycle of B and V light curves of IMXB HZ Her/Her X-1

ABSTRACT The X-ray binary Her X-1 consists of an accreting neutron star and the optical component HZ Her. The 35-d X-ray superorbital variability of this system is known, since its discovery in 1972 by the Uhuru satellite and is believed to be caused by forced precession of a warped accretion disc t...

Full description

Saved in:
Bibliographic Details
Published in:Monthly notices of the Royal Astronomical Society 2020-12, Vol.499 (2), p.1747-1757
Main Authors: Kolesnikov, D A, Shakura, N I, Postnov, K A, Volkov, I M, Bikmaev, I F, Irsmambetova, T R, Staubert, R, Wilms, J, Irtuganov, E, Golysheva, P Yu, Shugarov, S Yu, Nikolenko, I V, Trunkovsky, E M, Schönherr, G, Schwope, A, Klochkov, D
Format: Article
Language:English
Citations: Items that this one cites
Items that cite this one
Online Access:Request full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:ABSTRACT The X-ray binary Her X-1 consists of an accreting neutron star and the optical component HZ Her. The 35-d X-ray superorbital variability of this system is known, since its discovery in 1972 by the Uhuru satellite and is believed to be caused by forced precession of a warped accretion disc tilted to the orbital plane. We argue that the observed features of the 35-d optical variability of HZ Her can be explained by free precession of the neutron star with a period close to that of the forced disc. The model parameters include (a) the X-ray luminosity of the neutron star; (b) the optical flux from the accretion disc; and (c) the tilt of the inner and outer edges of the accretion disc. A possible synchronization mechanism based on the coupling between the neutron star free precession and the dynamical action of non-stationary gas streams is discussed.
ISSN:0035-8711
1365-2966
DOI:10.1093/mnras/staa2829