Generation of longitudinal flux tube waves in theoretical main-sequence stars: effects of model parameters

¹ Faculty of Engineering and Computer Sciences, Izmir University of Economics, 35330 Izmir, Turkey
e-mail: diaa.gadelmavla@izmirekonomi.edu.tr
² Department of Physics, Science Hall, University of Texas at Arlington, Arlington, TX 76019, USA
e-mail: cuntz@uta.edu
³ Institut für Theoretische Astrophysik, Universität Heidelberg, 69120 Heidelberg, Germany

Received: 21 June 2010
Accepted: 24 October 2010

Abstract

Aims. We compute the wave energy fluxes carried by longitudinal tube waves along vertically oriented thin magnetic fluxes tubes embedded in the atmospheres of theoretical main-sequence stars based on stellar parameters deduced by Kurucz and Gray. In addition, we present a fitting formula for the wave energy flux based on the governing stellar and magnetic parameters.

Methods. A modified theory of turbulence generation based on the mixing-length concept is combined with the magneto-hydrodynamic equations to numerically account for the wave energies generated at the base of magnetic flux tubes.

Results. The results indicate a stiff dependence of the generated wave energy on the stellar and magnetic parameters in principal agreement with previous studies. The wave energy flux F_LTW decreases by about a factor of 1.7 between G0 V and K0 V stars, but drops by almost two orders of magnitude between K0 V and M0 V stars. In addition, the values for F_LTW are significantly higher for lower in-tube magnetic field strengths. Both results are consistent with the findings from previous studies.

Conclusions. Our study complements existing descriptions of magnetic energy generation in late-type main-sequence stars. Our results will be helpful for calculating theoretical atmospheric models for stars of different levels of magnetic activity.