Magnetic Fields of Massive Stars

Sammanfattning: This paper is an introduction to the subject of magnetic fields on stars, with a focus on hotter stars. Basic astrophysical concepts are explained, including: spectroscopy, stellar classification, general structure and evolution of stars. The Zeeman effect and how absorption line splitting  is used to detect and measure magnetic fields is explained. The properties of a prominent type of magnetic massive star, Ap-stars, are delved into. These stars have very stable, global, roughly dipolar magnetic fields theorized to have been captured during star formation and maintained  throughout their lifetime. Different approaches to making models of the magnetic field of massive stars are explained, in particular the oblique rotator model. Finally, the use of the oblique rotator model is illustrated by finding possible field structures that would reproduce magnetic field observations of the star HD 37776.This paper is an introduction to the subject of magnetic fields on stars, with a focus on hotter stars. Basic astrophysical concepts are explained, including: spectroscopy, stellar classification, general structure and evolution of stars. The Zeeman effect and how absorption line splitting  is used to detect and measure magnetic fields is explained. The properties of a prominent type of magnetic massive star, Ap-stars, are delved into. These stars have very stable, global, roughly dipolar magnetic fields theorized to have been captured during star formation and maintained  throughout their lifetime. Different approaches to making models of the magnetic field of massive stars are explained, in particular the oblique rotator model. Finally, the use of the oblique rotator model is illustrated by finding possible field structures that would reproduce magnetic field observations of the star HD 37776.