W. Rammacher

Institut für Sonnenphysik

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P. Ulmschneider

Heidelberg University

Z. E. Musielak

The University of Texas at Arlington

M. Cuntz

The University of Texas at Arlington

Diaa E. Fawzy

İzmir University of Economics

K. Stępień

Lodz University of Technology

Steven H. Saar

Center for Astrophysics Harvard & Smithsonian

C. Beck

National Solar Observatory

R. Hammer

Institut für Sonnenphysik

O. Steiner

Institut für Sonnenphysik

Sven Wedemeyer

University of Oslo

Cooperative Institutions

Institut für Sonnenphysik

Heidelberg University

Purple Mountain Observatory

Heidelberg Institute for Theoretical Studies

Heidelberg University

Instituto de Astrofísica de Canarias

University of Freiburg

Harvard University

Center for Astrophysics Harvard & Smithsonian

Smithsonian Astrophysical Observatory

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Two-Component Chromosphere Models for K Dwarf Stars: The Chromospheric Emission --- Stellar Rotation Relationship

AAS (1998)

M. Cuntz Z. E. Musielak P. Ulmschneider W. Rammacher Steven H. Saar

Chromosphere

Component (thermodynamics)

Stellar rotation

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Acoustic Heating Models for the Basal Flux Star Ceti Including Time-dependent Ionization: Results for Ca ii and Mg ii Emission

The Astrophysical Journal (2003)

W. Rammacher M. Cuntz

We present new calculations of chromospheric heating for τ Ceti (G8 V), a star exhibiting an extremely low level of chromospheric activity, thus also referred to as a basal flux star or a flat activity star. Our simulations consider energy deposition by acoustic shocks and also take into account time-dependent (i.e., noninstantaneous) ionization processes of hydrogen, magnesium, and calcium, allowing us to attain a new generation of chromospheric heating models previously obtained for the Sun. We consider both monochromatic waves and acoustic frequency spectra. The latter are calculated using new models of acoustic energy generation based on an extended Kolmogorov spectrum with a modified Gaussian frequency factor. Our models show that the theoretically deduced emergent Ca II and Mg II emission very much agree with observations, adding to the argument that the chromospheres of basal flux stars are predominantly heated by acoustic shocks.

Energy flux

Star (game theory)

10.1086/378312

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Citations (14)