Abstract We compute the light curves of soft X-ray transients in the framework of the mass transfer instability model of Hameury et al. /1/. In this model, the atmosphere of the secondary star is heated by X-rays from the primary and develops an instability when the X-ray flux becomes comparable to the intrinsic stellar flux. We calculate the structure of the illuminated mass losing envelope during the transient event and find that the atmosphere is isothermal down to about 100 Thompson optical depths, as a result of inward radiative heat transport. This strongly reinforces the instability. The accretion rate on to the compact object is then computed using a time-dependent numerical code to describe the accretion disc. We find that the observed light curves are well reproduced if one takes the Shakura-Sunyaev α parameter of the order of unity, the rise times we obtain are of the order of days, and decay times are of the order of weeks.
The light curves of soft X-ray transients
Advances in Space Research ; 8 , 2-3 ; 489-492
1988-01-01
4 pages
Aufsatz (Zeitschrift)
Elektronische Ressource
Englisch
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