New insights on the interior of solar-like pulsators thanks to CoRoT: the case of HD 49385

TL;DR

This paper uses CoRoT space data to analyze the oscillations of the star HD 49385, revealing complex mode interactions that suggest it is in a Post Main Sequence evolutionary stage.

Contribution

It extends the analogy of avoided crossings to multiple modes, providing new insights into stellar interior modeling for solar-like pulsators.

Findings

Observation of characteristic eigenfrequency behavior in HD 49385

Inference that HD 49385 is in a Post Main Sequence phase

Extension of avoided crossing analogy to n modes

Abstract

The high performance photometric data obtained with space mission CoRoT offer the opportunity to efficiently constrain our models for the stellar interior of solar-like pulsating stars. On the occasion of the analysis of the oscillations of solar-like pulsator HD 49385, a G0-type star in an advanced stage of evolution, we revisit the phenomenon of the avoided crossings. Christensen-Dalsgaard proposed a simple analogy to describe an avoided crossing between two modes. We here present an extension of this analogy to the case of $n$ modes, and show that it should lead, in certain cases, to a characteristic behavior of the eigenfrequencies, significantly different from the $n=2$ case. This type of behavior seems to be observed in HD 49385, from which we infer that the star should be in a Post Main Sequence phase.