A study of magnetic fields in AP SI and He weak stars.
Abstract
A survey of 44 Ap and Bp Si and He-weak stars for the presence of detectable longitudinal magnetic fields (Be) is reported. Fields have been detected in about half of the sample, with typical standard errors in the range of 100-400 G. In 11 stars, fields have been detected for the first time. For most of the stars with detected fields, the variation of Be with rotational phase has been determined at least approximately. In a number of cases the phase relationship with photometric or spectroscopic variations have also been established. Several of the newly detected fields are relatively large, with rms values between 1 and 4 kG, and thus may be especially suitable for detailed mapping and modelling. A particularly interesting result of these observations is the identification of at least four stars in which extrema of the photometric or spectroscopic variations do not coincide with the magnetic extrema, which implies that the distribution of chemical elements over the stellar surface that leads to photometric variations is definitely not symmetric about the magnetic axis of the star.
- Publication:
-
Astronomy and Astrophysics
- Pub Date:
- March 1993
- Bibcode:
- 1993A&A...269..355B
- Keywords:
-
- A Stars;
- B Stars;
- Peculiar Stars;
- Silicon;
- Stellar Magnetic Fields;
- Helium;
- Stellar Spectrophotometry;
- Astrophysics