The magnetic field of the helium-strong stars

Abstract

A search for magnetic fields in eight helium-strong stars has revealed strong magnetic fields in HD 37017, HD 37776, HD 58260, HD 64740, and HD 96446. With the previous discovery of a magnetic field in Sigma Ori E this brings to six (out of nine observed) the number of magnetic helium-strong stars. This result confirms the hypothesis that the helium-strong stars are a hot extension of the Ap phenomenon. The possibility is considered that mass loss on the main sequence is responsible for the apparent division among the helium stars into rapid and slow rotators, but it is concluded that such mass loss is probably incapable of significantly slowing down a rapidly rotating helium-strong star.