Open AccessOn the precession of accretion discs in X‐ray binaries
Author(s) -
Larwood J.
Publication year - 1998
Publication title -
monthly notices of the royal astronomical society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.058
H-Index - 383
eISSN - 1365-2966
pISSN - 0035-8711
DOI - 10.1046/j.1365-8711.1998.01978.x
Subject(s) - precession , physics , accretion (finance) , astrophysics , accretion disc , binary number , astronomy , orbital period , stars , arithmetic , mathematics
In this Letter, recent results on the nodal precession of accretion discs in close binaries are applied to the discs in some X‐ray binary systems. The ratio between the tidally forced precession period and the binary orbital period is given, as well as the condition required for the rigid precession of gaseous Keplerian discs. Hence the minimum precessional period that may be supported by a fluid Keplerian disc is determined. It is concluded that near‐rigid body precession of tilted accretion discs can occur and generally reproduce observationally inferred precession periods, for reasonable system parameters. In particular, long periods in SS 433, Her X‐1, LMC X‐4 and SMC X‐1 can be fitted by the tidal model. It is also found that the precession period that has been tentatively put forward for Cyg X‐2 cannot be accommodated by a tidally precessing disc model for any realistic choice of system parameters.