On the Origin of Bright Lines in Spectra of Stars of Class B

It is found that stars of class B, having widely separated double bright lines are characterized by extremely flat and broad absorption lines suggestive of rapid axial rotation, of the order of several hundred km/sec. Stars having narrow, single emission lines, few in number, show little rotation. The suggestion is now offered that rapidly rotating single stars of spectral class B are unstable, and form lens-shaped bodies which eject matter at the equator, thus forming a nebulous ring which revolves around the star and gives rise to emission lines. The in- clination of the star's axis would then be responsible for the observed range in width of the emission lines