POLARIMETRY OF THE ECLIPSING POLAR RX J0929.1-2404

We report polarimetric, spectropolarimetric and photometric observatio ns of the eclipsing ROSAT cataclysmic variable RX J0929.1 -2404, which confirm that the system is a new polar (AM Herculis system). This bri ngs the number of eclipsing polars to nine, with RX J0929.1 -2404 bein g only the third such system above the period gap. Circular polarizati on variations from similar to-20 to 10 per cent are seen over the 3.39 -h orbital period, with a minimum around the time of eclipse. The phot opolarimetric data were modelled using are-shaped cyclotron emission r egions in a centred dipole geometry. Results imply that RX J0929.1 -24 04 is a 'two-pole' system, with one emission region partially visible at all orbital phases. Spectropolarimetry observations show some evide nce for the presence of cyclotron humps in the continuum, with spacing s consistent with a magnetic field strength of similar to 20 MG. Photo metry of the eclipses provides information on the size of the emission region, which is consistent with a hotspot on the surface of the whit e dwarf. The eclipse duration implies an inclination in the range 70 d egrees less than or similar to i less than or similar to 78 degrees.