MAGNETIC-FIELDS AT THE SURFACES OF STARS

被引:138
作者
LANDSTREET, JD
机构
[1] Department of Astronomy, University of Western Ontario, London, N6A 3K7, Ontario
[2] Observatoire Midi-Pyrénées, Toulouse, F-31400, 14, ave. Edouard-Belin
关键词
MAGNETIC FIELD; STARS; ACTIVITY OF; PECULIAR A; WHITE DWARF;
D O I
10.1007/BF00873569
中图分类号
P1 [天文学];
学科分类号
0704 ;
摘要
Magnetic fields have now been detected in stars in several parts of the Hertzsprung-Russell diagram. Roughly dipolar fields ranging in strength between 3 X 10(2) and 3 X 10(4) G are found in many chemically peculiar A and B main sequence stars. Dipolar fields are also found in some 2-3% of white dwarfs, but with strengths between 1 X 10(6) and 5 X 10(8) G. In both these types of stars, the observed fields vary as the underlying star tums, but do not change in a secular manner. In solar-type stars, structurally complex fields of a few kG are found with filling factors of the order of 0.1 to 0.8. Further indirect evidence of fields in cool main sequence stars is provided by detection of visible and ultraviolet line emission (chromospheric activity), x radiation (coronal matter), and giant starspots. In this review, we survey the observations of stellar magnetism in all these types of stars, as well as efforts to model the observed magnetic fields and associated photospheric peculiarities and activity.
引用
收藏
页码:35 / 77
页数:43
相关论文
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