An analysis of the cyclotron spectrum and polarization properties of VV Puppis

An analysis is presented of the cyclotron spectrum of VV Puppis using a model which allows for polarization and radiative transfer effects. It is shown that the cyclotron features arise in emission from a region with T = approximately 10 keV, B = 3.2 x 107G and Λ = 105, which emits strongly polarized radiation in the optical. The emission region is physically thin (height << cross-sectional radius) and is dominated by cyclotron cooling. There is also evidence for a second component of radiation which is essentially unpolarized and dominates in the blue region of the spectrum. The observed constancy of the cyclotron spectrum with orbital phase restricts the orbital inclination i and the angle between the rotation axis and the magnetic field α to the ranges 0 < i < approximately 30, 900 < α < approximately 1000 and 800 approximately < i =< 900, 1500 =< α < 1800 if the field is normal to the stellar surface. (author)