UBV photometry of V360 Lac

An analysis of an extensive collection of photometric and spectroscopic observations of the little studied bright Be star V360 Lac lead to the following main conclusions: (1) V360 Lac is a binary system consisting of a B3e primary and a F9IV secondary which probably fills the Roche lobe and losses mass towards the primary. Radial-velocity curves of both components were obtained. (2) The light variations arise from superposition of variations on at least three time scales: phase-locked orbital brightness and colour changes with two minima; sinusoidal variation with a 322.24^d^ period and low-amplitude rapid changes with a possible period of 1.6738^d^.

(3) A tentative solution of the B and V light curves which assumes the semi-detached configuration and presence of a disk around the primary, combined with the orbital solution, leads to preliminary basic physical elements of the system which are consistent with the radiative properties of the binary components.