C. Jiang, J. Christensen-Dalsgaard, M. S. Cunha
Abstract
Mixed modes have been extensively observed in post-main-sequence stars by the Kepler and CoRoT space missions. The mixture of the p and g modes can be measured by the dimensionless coefficient q, the so-called coupling strength factor. In this paper, we discuss the utility of the phase shifts theta from the eigenvalue condition for mixed modes as a tool to characterize dipolar mixed modes from the theoretical as well as the practical point of view. Unlike the coupling strength, whose variation in a given star is very small over the relevant frequency range, the phase shifts vary significantly for different modes. The analysis in terms of theta can also provide a better understanding of the pressure and gravity radial order for a given mixed mode. Observed frequencies of the Kepler red-giant star KIC 3744043 are used to test the method. The results are very promising.
Keywords
stars: interiors; stars: oscillations; stars: solar-type; Astrophysics - Solar and Stellar Astrophysics
Monthly Notices of the Royal Astronomical Society
Volume 474, Issue 4, Page 5413
2018 March
