The Jet from MWC 137 Points at a Supergiant B[e] Star in a Binary

The Galactic B[e] star MWC 137 is a prime example of an object with an uncertain evolutionary classification. Previous work has suggested that is either a pre- or a post-main sequence object. Integral field spectrograph observations with the Very Large Telescope Multi Unit Spectroscopic Explorer (VLT MUSE) of the host cluster SH 2-266 are used to provide a reliable evolutionary classification. The MUSE data also allowed the discovery of a large collimated outflow, geometrically centered on MWC 137. A color-magnitude diagram analysis of the cluster promotes strongly a post-main sequence stage for MWC 137, while the existence of a jet implies the presence of an accretion disk. A SWIFT X-ray source, which may be associated with MWC 137, hints at the possibility of a neutron star companion.