Stellar Magnetic Fields

Abstract

The study of the solar magnetic field was initiated in 1908, while that of stellar magnetic fields was only started in 1946. This is because stars are too far from us, and so much fainter and more difficult to observe than the Sun. Thanks to the efforts of astronomers through several generations, tremendous progress in both techniques of observation and theoretical interpretation of the stellar magnetism has been achieved in recent decades. The world of countless stars provides us with very abundant and colorful observational material. The solar general magnetic field has a strength of only 1–2 G, while many stars are characterized by extremely intense magnetic fields. For instance, the strength of the magnetic star HD 215441 is 34,400 G, and those of white dwarfs much stronger still: 10⁵–10⁷ G. It is surprising to learn that the magnetic field ofpulsars, which are generally interpreted to be fast rotating neutron stars, can even attain 10¹² G! Such intense magnetism may have a profound influence on the spectra, luminosity, chemical composition and physical status as well as the origin, structure and evolution of stellar objects. In this chapter we present a general account of all these problems. For further details the reader may consult the monographs of Cameron (1967) and Glagolevsky and Kopylov (1988) as well as the reviews of Landstreet (1980, 1992), Borra et al. (1982), Khokhlova (1985) and Mathys (1989).

Their magnetism works all night. Henry Vaughan (1622–1675), Silex Scintillans (1650).