Study of the magnetic field of the Ap star. beta. Coronae Borealis

Journal Article · Fri Sep 15 04:00:00 EDT 1978 · Astrophys. J.; (United States)

DOI:https://doi.org/10.1086/156441· OSTI ID:6652027

Freedman, R S

One of the outstanding characteristics of the Ap stars is the presence of a large, variable magnetic field. Using an offset oblique rotator model derived from observations of ..beta.. CrB, we calculated profiles of selected lines at three magnetic phases including explicitly the effects of the magnetic field. Profiles in left and right circularly polarized light were calculated and compared with the observations. Although line blending is a serious problem in this star, the profiles with the least blending agree reasonably well with the theoretical calculations. We also find that because of the geometry of the offset oblique rotator the rotation causes the profiles in the two polarizations to lose their mirror image property. The broadening due to the magnetic field also affects the curve of growth of a line: in general, it is not possible to represent the true curve of growth by using a conventional curve of growth with the addition of an extra amount of microturbulence. Our results also give no evidence that the gross atmospheric structure of ..beta.. CrB has been radically altered by the magnetic field, but more subtle changes cannot be ruled out.

• Research Organization: Astronomy Department, University of California, Berkeley
• OSTI ID: 6652027
• Journal Information: Astrophys. J.; (United States), Journal Name: Astrophys. J.; (United States) Vol. 224:3; ISSN ASJOA
• Country of Publication: United States
• Language: English

Related Subjects

640102* -- Astrophysics & Cosmology-- Stars & Quasi-Stellar
Radio & X-Ray Sources
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
ATMOSPHERES
ENERGY SPECTRA
FUNCTIONS
LINE WIDTHS
MAGNETIC FIELDS
MAGNETIC STARS
MATHEMATICAL MODELS
MOTION
POLARIZATION
ROTATION
SCATTERING
SPECTRA
SPECTRAL FUNCTIONS
STAR MODELS
STARS
STELLAR ATMOSPHERES
VARIABLE STARS