Frequencies analysis of the hybrid delta Sct-gamma Dor star CoRoT-102314644

TL;DR

This study analyzes the frequency spectrum of the hybrid delta Sct-gamma Dor star CoRoT-102314644 using space-based observations, revealing detailed pulsation modes, potential surface spots, and refining its stellar parameters for asteroseismic insights.

Contribution

It provides a detailed frequency analysis of a hybrid star, identifying multiple pulsation modes and constraining stellar parameters, advancing asteroseismology of A-F type stars.

Findings

Detected 29 gamma Dor frequencies and 38 delta Sct frequencies.

Identified a period spacing of 1612 seconds and a quintuplet around 11.39 c/d.

Estimated stellar parameters: mass ~1.75 M_sun, radius ~2.48 R_sun, age ~1241 Myr.

Abstract

Observations from space missions have allowed significant progress in many scientific domains due to the absence of atmospheric noise contributions and having uninterrupted data sets. In the context of asteroseismology, this has been extremely beneficial because many oscillation frequencies with small amplitudes, not observable from the ground, can be detected. One example of this success is the large number of hybrid delta Sct-gamma Dor stars discovered. These stars have radial and non-radial p- and g-modes simultaneously excited to an observable level allowing us to probe both the external and near-to-core layers of the star. We analyse the light curve of hybrid delta Sct-gamma Dor star CoRoT ID 102314644 and characterise its frequency spectrum. We detected 29 gamma Dor type frequencies in the range [0.32-3.66] cycles per day (c/d) and a series of 6 equidistant periods with a mean period spacing of DeltaPi=1612 s. In the delta Sct domain we found 38 frequencies in the range 8.63-24.73 c/d and a quintuplet centred on the frequency p_1=11.39 c/d and derived a possible rotational period of 3.06 d. The frequency analysis of this object suggests the presence of spots at the stellar surface, nevertheless we could not dismiss the possibility of a binary system. The initial modelling of the frequency data along with external constraints has allowed us to refine its astrophysical parameters giving a mass of approximately 1.75 solar masses, a radius of 2.48 solar radii and an age of 1241 Myr. The observed period spacing, a p-mode quintuplet, the possible rotation period and the analysis of the individual frequencies provide important input constraints for the understanding of different transport phenomena in A-F-type stars.[abridged]