2018MNRAS.476.3039R

Double Periodic Variables (DPV) are among the new enigmas of semidetached eclipsing binaries. These are intermediate-mass binaries characterized by a long photometric period lasting on average 33 times the orbital period. We present a spectroscopic and photometric study of the DPV V495 Cen based on new high-resolution spectra and the ASAS V-band light curve. We have determined an improved orbital period of 33.492 ± 0.002 d and a long period of 1283 d. We find a cool evolved star of M₂=0.91±0.2 M_☉, T₂ = 6000 ± 250 K and R₂=19.3 ±0.5 R_☉ and a hot companion of M₁= 5.76±0.3 M_☉, T₁ = 16960 ± 400 K and R=4.5±0.2 R_☉. The mid-type B dwarf is surrounded by a concave and geometrically thick disc, of radial extension R_d= 40.2±1.3 R_☉ contributing ∼11 per cent to the total luminosity of the system at the V band. The system is seen under inclination 84^○_.8 ± 0^○_.6 and it is at a distance d = 2092 ± 104.6 pc. The light-curve analysis suggests that the mass transfer stream impacts the external edge of the disc forming a hot region 11 per cent hotter than the surrounding disc material. The persistent V < R asymmetry of the Hα emission suggests the presence of a wind and the detection of a secondary absorption component in He I lines indicates a possible wind origin in the hotspot region.