Tidally Perturbed Oblique Pulsations in the Hierarchical Triple System V1031 Orionis

TL;DR

This study analyzes TESS data of the triple star system V1031 Ori, revealing tidally perturbed pulsations in the secondary star and providing precise stellar parameters through combined photometric and spectroscopic analysis.

Contribution

It presents the first detailed analysis of tidally perturbed pulsations in a hierarchical triple system, combining high-quality photometry with spectroscopic data for comprehensive stellar characterization.

Findings

Identified 7 p-mode frequencies modulated by the binary orbit.

Detected amplitude modulation of pulsations with orbital phase.

Determined stellar masses and radii with high precision.

Abstract

We present TESS photometry of the triple star system V1031 Ori (AB)C, which exhibits short-period oscillations superimposed on an eclipsing light curve. The high-quality data were analyzed in detail and combined with the published spectroscopic measurements to obtain the fundamental stellar parameters of the program target. The masses and radii of the eclipsing pair (AB) were determined to about 0.5 \% and 0.7 \% precision, respectively. We found 23 significant frequencies in two ranges of $<$ 2 day$^{-1}$ and 10.9$-$12.7 day$^{-1}$ from the eclipse-subtracted residuals. Among them, sixteen in the gravity ($g$)-mode region may be aliases and artefacts due to imperfect removal of the systematic trends and the binary effects from the TESS data. Seven frequencies in the pressure ($p$)-mode region were separated by the orbital frequency and split by the average offset of 0.042 $\pm$ 0.003 day$^{-1}$ from their adjacent harmonics. Further, the pulsation amplitudes are clearly modulated with the binary star orbit. The results indicate that the $p$-mode frequencies are tidally perturbed pulsations from the secondary component and the pulsation axis could be aligned with the tidal axis.