Berlin 2014 – wissenschaftliches Programm

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EP: Fachverband Extraterrestrische Physik

EP 5: Postersitzung

EP 5.25: Poster

Dienstag, 18. März 2014, 16:30–18:30, DO24 Foyer

The prediction of stellar atmospheric oscillations as a result of propagating magnetic tube waves — •Diaa Fawzy¹ and Zdzislaw Musielak² — ¹Izmir University of Economics, Izmir, Turkey — ²Physics dept., University of Texas at Arlington, USA

In the current study we theoretically predict atmospheric oscillations in a thin and non-isothermal magnetic flux tube embedded in magnetic-free atmospheres of late-type stars. Our models are based on self-consistent, nonlinear and time-dependent numerical computations. Longitudinal tube waves are considered and the wave energy spectra and fluxes generated in convective zones of these stars are calculated. The process of filtering the energy carried by longitudinal tube waves is investigated and both the local heating by shock waves as well as the excitation of atmospheric oscillations are studied. Frequencies of the resulting atmospheric oscillations are computed numerically at different atmospheric heights in stars of different effective temperatures and gravities, and compared to three analytically obtained cutoff frequencies. The obtained results show that the oscillation frequency ranges from 4 mHz for F5V stars to 20 mHz for M0V stars. It is pointed out that this frequency range may be relevant to the recent stellar p-mode observations made by the NASA space mission Kepler.