1994A&A...284L..27M

We report the presence of Brα and Brγ emission features in the infrared spectrum of the O9V MK standard star 10 Lac. Waters et al. (1993) have reported similar emission in the spectrum of the B0.2V star τ Sco and have suggested that the emission is from a low-density disk and that τ Sco is a mild, pole-on member of the Be class of stars. We argue that such emission features arise as a natural consequence of the structure of these stars'outer atmospheres, thus eliminating the need to introduce departures from spherical symmetry. Indeed, theoretical Brα and Brγ line profiles calculated using stellar parameters derived from 10 Lac by Grigsby et al. (1992) show a striking similarity to our observations