The evolution stage and massive disc of the interacting binary V 393 Scorpii

• Published in: Monthly notices of the Royal Astronomical Society Vol. 421; no. 1; pp. 862 - 871
• Main Authors: Mennickent, R. E., Djurašević, G., Kołaczkowski, Z., Michalska, G.
• Format: Journal Article
• Language: English
• Published: Oxford, UK Blackwell Publishing Ltd 01-03-2012
• Subjects: stars: early‐type; stars: emission‐line, Be; stars: evolution; stars: mass‐loss; stars: variables: general; stars: mass-loss; stars: early-type; stars: emission-line, Be; stars: evolution; stars: variables: general
• ISSN: 0035-8711; 1365-2966
• DOI: 10.1111/j.1365-2966.2011.20363.x

V 393 Scorpii is a bright Galactic Double Periodic Variable showing a long photometric cycle of ≈253 d. We present new VIJK photometric time series for V 393 Scorpii along with the analysis of All Sky Automated Survey (ASAS) V-band photometry. We disentangled all light curves into the orbital and long-cycle components. The ASAS V-band orbital light curve was modelled with two stellar components plus a circumprimary optically thick disc assuming a semi-detached configuration. We present the results of this calculation, giving physical parameters for the stars and the disc, along with general system dimensions. Our results are in close agreement with those previously found by Mennickent et al. from infrared (IR) spectroscopy and the modelling of the spectral energy distribution. The stability of the orbital light curve suggests that the stellar plus disc configuration remains stable during the long cycle. Therefore, the long cycle should be produced by an additional variable and not-eclipsed emitting structure. We discuss the evolutionary stage of the system finding the best match with one of the evolutionary models of van Rensbergen et al. According to these models, the system is found to be after an episode of fast mass exchange that transferred 4 M⊙ from the donor to the gainer in a period of 400 000 years. We argue that a significant fraction of this mass has not been accreted by the gainer but remains in an optically thick massive (∼2 M⊙) disc-like surrounding pseudo-photosphere whose luminosity is not driven by viscosity but probably by reprocessed stellar radiation. Finally, we provide the result of our search for Galactic Double Periodic Variables and briefly discuss the outliers β Lyr and RX Cas.