Infrared spectroscopy of the long-period polar RXJ0515.6+0105

We present K-band (1.81-2.44 mu m) spectroscopy of the 7.98-h orbital period polar RXJ0515.6 + 0105. Spectra obtained around orbital phase 0.5 reveal strong emission lines of neutral hydrogen and helium from the accretion stream. No obvious spectral features from the secondary star are detected: the K-band emission is dominated instead by cyclotron radiation from the accretion region. We find that the slope of the cyclotron spectrum is consistent with a magnetic field strength of 60 MG, in agreement with previous optical studies and with the results from our modelling of previous white-light polarimetry. We estimate that the secondary contributes less than similar to 20 per cent of the infrared flux, implying a distance greater than similar to 1500 pc. With this result, we estimate the mass transfer rate to be greater than similar to 1.0 x 10(17) g s(-1). We show that it is plausible that the system is synchronized with the derived values of the mass transfer rate and with a primary magnetic field strength of 60 MG.