DIFFERENCE BETWEEN BE STARS AND SHELL STARS FROM H-ALPHA EMISSION

We examine Ha equivalent widths versus spectral-types for 41 Be stars. Although the W-alpha value is scattered for a given spectral-type, a well-defined upper limit exists. Most shell stars are located in the upper limit region. The shell stars all have v sin i/v(cri) larger than the normal Be stars in the upper limit region. This strongly suggests that the distinction between shell stars and normal Be stars of high equivalent width is a result of variation in inclination angle i. Polarization data also support this hypothesis.