INFRARED-EMISSION LINES IN TAU-SCORPII - A POLE-ON BE STAR

We report the discovery of Bralpha and Brgamma emission in the infrare d spectrum of the B0.2 V star tau Scorpii. The widths and strengths of the lines suggest that they are formed in a region of much higher den sity than is inferred from the UV resonance lines. This situation is s imilar to that found in Oe and Be stars. We show that the IR emission lines in tau Scorpii can be produced in a circumstellax disc of modera te density, without producing noticeable emission in Halpha. It is pos sible that a class of 'hidden' Be stars exists whose emission is promi nent in the IR recombination lines but not in Halpha.