Polars: Emission from
post-shock flow
€Given the run of temperature and density, and assuming collisional ionisation (for this density regime) it is possible to show that the emission region is optically thin to X-rays
€Also possible to calculate the ionisation fraction of any ion species, and therefore the emissivity, as a function of height in the post-shock flow as well as parameters such as
–mass of the white dwarf
–accretion rate
€Predictions can be matched to spectra and continuum emission to derive fundamental parameters –
X-ray calorimetry
Cropper, Wu & Ramsay (2000)
Wu, Cropper &
Ramsay (2001)