2005A&A...442L..61B

We report on EVN imaging of the 6.7GHz methanol maser emission from the candidate high-mass protostar G23.657-0.127. The masers originate in a nearly circular ring of 127mas radius and 12mas width. The ring structure points at a central exciting object which characteristics are typical for a young massive star; its bolometric luminosity is estimated to be ≤3.2x10⁴L_☉ and ≤1.2x10⁵L_☉ for near (5.1kpc) and far (10.5kpc) kinematic distances, respectively. However, the spatial geometry of the underlying maser region remains ambiguous. We consider scenarios in which the methanol masers originate in a spherical bubble or in a rotating disc seen nearly face-on.