Asteroseismology with TESS: Emergence of Dipole Mode Suppression From Subgiants?

TL;DR

This study analyzes TESS data to identify the emergence of dipole mode suppression in evolved giant stars, revealing that suppression begins earlier than previously thought, especially near the base of the red-giant branch.

Contribution

It provides new observational evidence that dipole mode suppression occurs in subgiants and earlier in stellar evolution than previously documented.

Findings

179 stars with dipole mode depression identified

Suppression starts near the base of the red-giant branch

Mode suppression appears earlier than previous Kepler-based studies

Abstract

Dipole mode suppression is an observed behavior of solar-like oscillations in evolved stars. This study aims to search for depressed dipole modes in giant stars using data from the Transiting Exoplanet Survey Satellite (TESS) and investigate when the suppression starts to emerge. We study a sample of 8,651 TESS-evolved stars and find 179 stars with significant dipole mode depression by comparing the oscillation amplitudes of radial and dipole modes. Notably, 11 of them are located near the base of the red-giant branch, indicating that mode suppression appears earlier than the point inferred in previous studies with the Kepler data. These findings provide new evidence for the dipole mode suppression in giant stars, particularly in subgiants.