Oscillations and Surface Rotation of Red Giant Stars

TL;DR

This study analyzes Kepler data of over 15,000 red giants to determine their oscillation properties, estimate their masses and radii, and detect surface rotation signatures through wavelet analysis.

Contribution

It provides the first estimation of masses and radii for a large sample of red giants and applies wavelet analysis to identify surface rotation signatures.

Findings

Determined global acoustic mode properties for 416 red giants.

Estimated stellar masses and radii using effective temperature data.

Detected surface rotation signatures in the stellar light curves.

Abstract

More than 15000 red giants observed by Kepler for a duration of almost one year became public at the beginning of this year. We analysed a subsample of 416 stars to determine the global properties of acoustic modes (mean large separation and frequency of maximum power). Using the effective temperature from the Kepler Input Catalog, we derived a first estimation of the masses and radii of these stars. Finally, we applied wavelets to look for signature of surface rotation, which relies on the presence of spots or other surface features crossing the stellar visible disk.