TIC 435850195: The Second Tri-Axial, Tidally Tilted Pulsator

TL;DR

This paper reports the discovery and analysis of the second known tri-axial pulsator star, revealing complex pulsation modes and providing a framework for future studies of such stars using TESS data.

Contribution

It introduces the first detailed analysis of a second tri-axial pulsator, identifying its pulsation modes and developing a modeling framework for these stars.

Findings

Discovered the second tri-axial pulsator with 16 pulsation multiplets.

Identified dominant pulsation modes as $Y_{10x}$ and $Y_{10y}$.

Excluded the presence of $Y_{11x}$ modes in the star.

Abstract

The Transiting Exoplanet Survey Satellite (TESS) has enabled the discovery of numerous tidally tilted pulsators (TTPs), which are pulsating stars in close binaries where the presence of a tidal bulge has the effect of tilting the primary star's pulsation axes into the orbital plane. Recently, the modeling framework developed to analyze TTPs has been applied to the emerging class of tri-axial pulsators, which exhibit nonradial pulsations about three perpendicular axes. In this work, we report on the identification of the second-ever discovered tri-axial pulsator, with sixteen robustly-detected pulsation multiplets, of which fourteen are dipole doublets separated by 2$\nu_{\rm orb}$. We jointly fit the spectral energy distribution (SED) and TESS light curve of the star, and find that the primary is slightly evolved off the zero-age main sequence, while the less massive secondary still lies on the zero-age main sequence. Of the fourteen doublets, we associate eight with $Y_{10x}$ modes and six with novel $Y_{10y}$ modes. We exclude the existence of $Y_{11x}$ modes in this star and show that the observed pulsation modes must be $Y_{10y}$. We also present a toy model for the tri-axial pulsation framework in the context of this star. The techniques presented here can be utilized to rapidly analyze and confirm future tri-axial pulsator candidates.