Modeling Kepler Observations of Solar-like Oscillations in the Red-giant Star HD 186355

TL;DR

This study analyzes Kepler data of the red giant HD 186355 to extract oscillation frequencies, estimate stellar parameters, and determine its evolutionary phase using asteroseismic scaling relations and stellar modeling.

Contribution

It provides the first detailed asteroseismic analysis of HD 186355, combining observational data with stellar models to determine its fundamental properties and evolutionary status.

Findings

Oscillation frequencies accurately extracted from Kepler data.

Estimated stellar mass of approximately 1.45 solar masses.

Identified mixed modes indicating shell hydrogen-burning phase.

Abstract

We have analysed oscillations of the red giant star HD 186355 observed by the NASA Kepler satellite. The data consist of the first five quarters of science operations of Kepler, which cover about 13 months. The high-precision time-series data allow us to accurately extract the oscillation frequencies from the power spectrum. We find the frequency of the maximum oscillation power, {\nu}_max, and the mean large frequency separation, {\Delta}{\nu}, are around 106 and 9.4 {\mu}Hz respectively. A regular pattern of radial and non-radial oscillation modes is identified by stacking the power spectra in an echelle diagram. We use the scaling relations of {\Delta}{\nu} and {\nu}_max to estimate the preliminary asteroseismic mass, which is confirmed with the modelling result (M = 1.45 \pm 0.05 M_sun) using the Yale Rotating stellar Evolution Code (YREC7). In addition, we constrain the effective temperature, luminosity and radius from comparisons between observational constraints and models. A number of mixed l = 1 modes are also detected and taken into account in our model comparisons. We find a mean observational period spacing for these mixed modes of about 58 s, suggesting that this red giant branch star is in the shell hydrogen-burning phase.