首页    期刊浏览 2024年12月05日 星期四
登录注册

文章基本信息

  • 标题:The crucial role of surface magnetic fields for stellar dynamos: ϵ Eridani, 61 Cygni A, and the Sun
  • 本地全文:下载
  • 作者:S.V.Jeffers ; R.H.Cameron ; S.C.Marsden
  • 期刊名称:Astronomy & Astrophysics
  • 印刷版ISSN:0004-6361
  • 电子版ISSN:1432-0746
  • 出版年度:2022
  • 卷号:661
  • 页码:1-8
  • DOI:10.1051/0004-6361/202142202
  • 语种:English
  • 出版社:EDP Sciences
  • 摘要:Cool main-sequence stars, such as the Sun, have magnetic fields which are generated by an internal dynamo mechanism. In the Sun, the dynamo mechanism produces a balance between the amounts of magnetic flux generated and lost over the Sun’s 11-year activity cycle and it is visible in the Sun’s different atmospheric layers using multi-wavelength observations. We used the same observational diagnostics, spanning several decades, to probe the emergence of magnetic flux on the two close by, active- and low-mass K dwarfs: 61 Cygni A and Eridani. Our results show that 61 Cygni A follows the Solar dynamo with a regular cycle at all wavelengths, while Eridani represents a more extreme level of the Solar dynamo, while also showing strong Solar-like characteristics. For the first time we show magnetic butterfly diagrams for stars other than the Sun. For the two K stars and the Sun, the rate at which the toroidal field is generated from surface poloidal field is similar to the rate at which toroidal flux is lost through flux emergence. This suggests that the surface field plays a crucial role in the dynamos of all three stars. Finally, for Eridani, we show that the two chromospheric cycle periods, of ∼3 and ∼13 years, correspond to two superimposed magnetic cycles.
  • 关键词:stars: activity;Sun: activity;stars: individual: 61 Cygni A;stars: individual: ϵ Eridani;stars: magnetic field
国家哲学社会科学文献中心版权所有