3. X-ray emission from post-shock gas
The X-ray emission from the hot post-shock gas can be calculated using the expressions for the density and temperature given above. The X-ray luminosity due to emission by the post-shock gas in the direction of the movement of the shock can be expressed as
in ergs s-1; ne, ni and T are dependent on x. Here ni=nHe, where nHe is the density of helium nuclei (the main constituent of the wind from the Wolf-Rayet star) in the wind and ne= 2ni; A is the area of the shock and is 2r, where rs is the radius of the shock and is 1.11011 cm (Apparao 1997). The integrals are over the temperature range and the frequency band. Using the expressions for the density and temperature profiles in the post-shock gas given by Apparao (1997), we have evaluated the X-ray luminosity between 2 and 12 kev and find Lx 1038 ergs s-1 which is comparable to the observed value(White and Holt 1982; Willingale et al. 1985). Note that Ts given above corresponds to 4.7 keV, therefore the X-ray emission from the post-shock gas corresponds to the soft component.
© European Southern Observatory (ESO) 2000
Online publication: February 25, 2000