V669 Cep: A new binary system with a B[e] star

Abstract

We present the results of optical and near-IR spectroscopic and broadband multicolour photometric observations of the emission-line object V669 Cep. We find evidence that it contains a hot, low luminosity, B4-B6 star and a cool companion (most likely late-type giant). Significant variations of the Hα line strength are detected on a timescale of months. The emission-line spectrum and strong IR-excess indicate a large amount of circumstellar gas and dust in the system. The spectral energy distribution in the near-IR region and the absence of late-type star features in the optical spectrum indicates that the cool star is heavily obscured by circumstellar dust, while the hot star is much less affected by reddening. The system is located at 1-1.5 kpc from the Sun in the local spiral arm. We suggest that V669 Cep is an evolved and probably mass exchanging binary system, a member of the group of Be stars with warm dust.