ON THE MAGNETIC NATURE OF GQ-MUSCAE

An observational study of the classical nova GQ Mus is presented. CCD photometry and time-resolved spectroscopic measurements are analyzed in the context of accretion onto a magnetic white dwarf. A long-term ephemeris and the light curve characteristics in the R filter are derived from photometric monitoring around the orbit. Radial velocity measurements confirm the orbital period of 85 minutes and indicate that the high ionization lines seen in the spectrum of this object like O VI lambda3811 are formed in the binary system. The analysis of the orbital variation in the line profile together with the Doppler imaging of the system suggest that a significant fraction of the He II lambda4686 line is produced in the surface of the secondary star. The analysis of the Doppler imaging in the light of He II lambda4686 favors the funneled accretion interpretation. The photometric data available for this system were used to model the main properties of the magnetically driven accretion in the system. As a result we claim the occurrence of a high accretion rate (M > 10(-8) M. yr-1) which causes the column to be optically thick and strong companion illumination effects.