Open AccessHydrodynamical winds from two‐temperature plasma in X‐ray binaries
Author(s) -
Lin David J.,
Misra R.,
Taam Ronald E.
Publication year - 2001
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.1365-8711.2001.04235.x
Subject(s) - physics , plasma , luminosity , astrophysics , electron temperature , compact star , binary number , computational physics , parameter space , electron , stars , geometry , nuclear physics , galaxy , arithmetic , mathematics
Hydrodynamical winds from a spherical two‐temperature plasma surrounding a compact object are constructed. The mass‐loss rate is computed as a function of electron temperature, optical depth and luminosity of the sphere, the values of which can be constrained by the fitting of the spectral energy distributions for known X‐ray binary systems. The sensitive dependence of the mass‐loss rate with these parameters leads to the identification of two distinct regions in the parameter space separating wind‐dominated from non‐wind‐dominated systems. A critical optical depth ( τ c ) is defined as a function of luminosity and electron temperature, which differentiates these two regions. Systems with optical depths significantly smaller than τ c are wind‐dominated. The results are applied to black hole candidate X‐ray binary systems in the hard spectral state (Cyg X‐1, GX 339−4 and Nova Muscae), and it is found that the inferred optical depth ( τ ) is similar to τ c , suggesting that they are wind‐regulated systems. On the other hand, for X‐ray binary systems containing a neutron star (e.g., Cyg X‐2) τ is much larger than τ c indicating the absence of significant hydrodynamical winds.