Open AccessX‐ray irradiation in low‐mass binary systems
Author(s) -
Dubus Guillaume,
Lasota JeanPierre,
Hameury JeanMarie,
Charles Phil
Publication year - 1999
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.1365-8711.1999.02212.x
Subject(s) - physics , accretion (finance) , astrophysics , irradiation , binary number , accretion disc , flux (metallurgy) , orbital plane , low mass , plane (geometry) , thermal , geometry , nuclear physics , thermodynamics , arithmetic , mathematics , stars , materials science , metallurgy
We calculate self‐consistent models of X‐ray‐irradiated accretion discs in close binary systems. We show that a point X‐ray source powered by accretion and located in the disc plane cannot modify the disc structure, mainly because of the self‐screening by the disc of its outer regions. As observations show that the emission of the outer disc regions in low‐mass X‐ray binaries is dominated by the reprocessed X‐ray flux, accretion discs in these systems must be either warped or irradiated by a source above the disc plane, or both. We analyse the thermal‐‐viscous stability of irradiated accretion discs and derive the stability criteria of such systems. We find that, contrary to the usual assumptions, the critical accretion rate below which a disc is unstable is rather uncertain because the correct formula describing irradiation is not well known.