2002A&A...383..171M

We present the results of optical and near-IR spectroscopic and broadband multicolour photometric observations of the emission-line star AS 381. Its properties were found to be similar to those of Be stars with warm dust, a group of galactic objects recently defined by Sheikina et al. (2000, ASP Conf. Ser., 214, 494). The spectrum of AS 381 indicates the presence of both a hot (early B-type) and a cool (K-type) star in the system. A high interstellar reddening (A_V∼7mag) suggests that it is located at a distance of ≥3kpc, and the companions have luminosity types ii or higher. The emission-line profiles indicate that the system is surrounded by a flattened circumstellar envelope, which is viewed close to pole-on. The hot companion is found to be ∼2mag brighter in the V-band and more massive (∼20M_☉) than the cool one (∼7M_☉). The strong line emission and position of the companions in the Hertzsprung-Russell diagram indicate that the system is experiencing mass exchange. We suggest that AS 381 is the first B[e] supergiant binary discovered in the Milky Way.