Optical spectroscopy of DPVs and the case of LP Ara

Instytut AstronomicznyUniwersytetu Wroc lawskiego, Wroc law, PolandAbstract.We present preliminary results of our spectroscopic campaign of a group of interme-diate mass interacting binaries dubbed “Double Periodic Variables” (DPVs), characterized byorbital light curves and additional long photometric cycles recurring roughly after 33 orbital pe-riods (Mennickent et al. 2003, 2005). They have been interpreted as interacting, semi-detachedbinaries showing cycles of mass loss into the interstellar medium (Mennickent et al. 2008, Men-nickent & Ko laczkowski 2009). High resolution Balmer and helium line profiles of DPVs can beinterpreted in terms of mass flows in these systems. A system solution is given for LPAra, basedon modeling of the ASAS V-band orbital light curve and the radial velocity of the donor star.Keywords.stars: binaries, stars: early-type