Acoustic and magnetic wave heating in stars - I. Theoretical chromospheric models and emerging radiative fluxes

被引:63
作者
Fawzy, D
Rammacher, W
Ulmschneider, P
Musielak, ZE
Stepien, K
机构
[1] Heidelberg Univ, Inst Theoret Astrophys, D-69121 Heidelberg, Germany
[2] Univ Texas, Dept Phys, Arlington, TX 76019 USA
[3] Univ Warsaw Observ, PL-00478 Warsaw, Poland
来源
ASTRONOMY & ASTROPHYSICS | 2002年 / 386卷 / 03期
关键词
methods : numerical; stars : chromospheres; stars : coronae; stars : magnetic fields; MHD; waves;
D O I
10.1051/0004-6361:20020256
中图分类号
P1 [天文学];
学科分类号
0704 ;
摘要
We describe a method to construct theoretical, time-dependent, two-component and wave heated chromosphere models for late-type dwarfs. The models depend only on four basic stellar parameters: effective temperature, gravity, metallicity and filling factor, which determines the coverage of these stars by surface magnetic fields. They consist of non-magnetic regions heated by acoustic waves and vertically oriented magnetic flux tubes heated by longitudinal tube waves with contributions from transverse tube waves. Acoustic, longitudinal and transverse wave energy spectra and fluxes generated in stellar convection zones are computed and used as input parameters for the theoretical models. The waves are allowed to propagate and heat both components by shock dissipation. We compute the time-dependent energy balance between the dissipated wave energy and the most prominent chromospheric radiative losses as function of height in the stellar atmosphere. For the flux tube covered stars, the emerging radiative fluxes in the Ca II and Mg II lines are computed by using a newly developed multi-ray radiative transfer method.
引用
收藏
页码:971 / 982
页数:12
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