A study of the interacting binary V 393 Scorpii
Abstract
We present high resolution J-band spectroscopy of V 393 Sco obtained with the CRIRES at the ESO Paranal Observatory along with a discussion of archival IUE spectra and published broad band magnitudes. The best fit to the spectral energy distribution outside eclipse gives T1= 19000 500 K for the gainer, T2= 7250 300 K for the donor, E(B-V)= 0.13 0.02 mag. and a distance of d= 523 60 pc, although circumstellar material was not considered in the fit. We argue that V 393 Sco is not a member of the open cluster M7. The shape of the He I 1083 nm line shows orbital modulations that can be interpreted in terms of an optically thick pseudo-photosphere mimicking a hot B-type star and relatively large equatorial mass loss through the Lagrangian L3 point during long cycle minimum. IUE spectra show several (usually asymmetric) absorption lines from highly ionized metals and a narrow Lα emission core on a broad absorption profile. The overall behavior of these lines suggests the existence of a wind at intermediate latitudes. From the analysis of the radial velocities we find M2/M1= 0.24 0.02 and a mass function of f= 4.76 0.24 M. Our observations favor equatorial mass loss rather than high latitude outflows as the cause for the long variability.