¹ Astrophysics Research Institute, Liverpool John Moores University, Byrom St., Liverpool, L3 3AF, U.K.
² SAX Science Data Center, ASI, c/o Nuova Telespazio, via Corcolle 19, I00131 Rome, Italy
³ Astronomy Centre, CPES, University of Sussex, Falmer, Brighton, BN1 9QH, U.K.
⁴ Departamento de Astronomía y Astrofísica, Universidad de Valencia, 46100 Burjassot, Valencia, Spain
⁵ Physics and Astronomy Department, Southampton University, Southampton, SO17 1BJ, U.K.

We present optical and infrared observations of BQ Cam, the optical counterpart to the Be/X-ray transient system V0332+53. BQ Cam is shown to be an O8-9Ve star, which places V0332+53 at a distance of  7 kpc. H spectroscopy and infrared photometry are used to discuss the evolution of the circumstellar envelope. Due to the low inclination of the system, parameters are strongly constrained. We find strong evidence for a tilt of the orbital plane with respect to the circumstellar disc (presumably on the equatorial plane). Even though the periastron distance is only  10R_*, during the present quiescent state the circumstellar disc does not extend to the distance of periastron passage. Under these conditions, X-ray emission is effectively prevented by centrifugal inhibition of accretion. The circumstellar disc is shown to be optically thick at optical and infrared wavelengths, which together with its small size, is taken as an indication of tidal truncation.

1999, MNRAS, 307, 695