Rotational Velocities of AP Stars.

Abstract

Rotational velocities have been obtained from coude spectra for the 63 brightest Ap stars; these velocities average 22% of those of the normal stars, using hyrodgen-line spectral types. it is shown that the idea that Ap stars are normal stars seen pole on is incompatible with the frequency distributions of rotational velocities. Assuming, therefore, random orientations of axes for both normal main-sequence and Ap stars, we find that there are no slowly rotating (V< 100 km/sec) normal stars in the range B7-AO and no rapidly rotating (V> 150 km/sec) Ap stars. Again assuming random orientations of axes, we find no serious inconsistencies between rotational periods and the periods of 16 spectrum variables, magnetic variables, and short-period spectroscopic binaries. Copyright 1967 by the ~