2001A&A...374..588S

Based on high-resolution optical spectroscopy in the blue and the near infra-red spectral range, we derived velocity images (Doppler tomograms) of the mass-donating secondary star and the accretion stream of the long-period eclipsing polar 13 (RX J0515.41+0104.6). Combined with HST-spectroscopy of high time resolution and optical photometry we were able to derive the main system parameters and to determine the accretion geometry of the binary. The length of the eclipse of the white dwarf is Δt_ecl=2418±60s, the mass ratio Q=1.37-1.63, and the orbital inclination i=76.6°-78.9°. The surface of the secondary star could be resolved in the Doppler image of NaI absorption lines, where it shows a marked depletion on the X-ray irradiated side. The accretion geometry proposed by us with a nearly aligned rotator, co-latitude δ≃10°, tilted away from the ballistic stream, azimuth χ≃-35°, explains the shape of the emission-line Doppler tomograms and the shape of optical/UV eclipse light curves.