Spectroscopic observations of post-common envelope binaries

We present spectroscopy of three post-common envelope binaries, with complete orbital coverage of RE 1016-053. For the latter target we have measured the radial velocities and line strengths and mapped the line emissivity on the surface of the secondary star using both these observational constraints simultaneously. We find that the emissivity is non-uniform over the surface of the star and, accounting for this, Kr=134 km s−1, the mass ratio q=0.5 and orbital inclination is 67 °. We find a secondary star mass of 0.285 M⊙ that corresponds to a spectral type of M3. For PG 1026+002 and RE 2013+400 we were able to update the ephemerides and investigate the widths of the Balmer emission lines. The width of the Balmer emission lines in RE 1016-053 and RE 2013+400 is such that they must be intrinsically broad with σintrin∼ 30-40 km s−1. Surprisingly this is not true for PG 1026+002 where the emission is unresolved. In PG 1026+002 the emission lines may be due to starspots rather than irradiation. The Ca ii emission in RE 1016-053 is also unresolved, as is expected. However, there appears to be no intrinsic Ca ii emission, contrary to expectations based on rotation rate–line strength relationships.