Magnetic fields of B and Herbig Ae stars measured with FORS1 at the VLT

摘要

We present the results of a magnetic survey with FORS 1 in po-larimetric mode of a sample of B and Herbig Ae stars with previously undetected magnetic fields. For the first time a mean longitudinal magnetic field at a level higher than 3a has been detected in one normal B star, two HgMn stars, one PGa star and four SPB stars. The observations of the three Herbig Ae stars (also known as Vega-like stars) reveal a definite longitudinal magnetic field in the star HD 139614 at 4.8 σ level: =-450 ± 93 G. This is the largest magnetic field ever diagnosed for a Herbig Ae star. A hint of a magnetic field is found in the other two stars, HD 144432 and HD 144668, for which magnetic fields are measured at the ～1.6 σ and ～2.5σ level respectively.