On the intrinsic rotation of magnetic variables

Abstract

It is observed that the rotational velocities of most Ap stars are dependent on their masses. Deviations from this general rule may be explained in terms of multiplicity which affects the derived colors and radii. Spectroscopic binaries are found to have lower rotational velocities than the corresponding single Ap stars. The slope of the relationship between intrinsic rotational velocity and color index appears to be the same for both single stars and binaries. Only in the case of spectroscopic binaries is there a zero point shift. Associated periods of 4.23 and 2.675 days for HD 140728 and 140160, respectively, are suggested. The 34 kG star, HD 215441, is possibly a spectroscopic binary seen pole-on.