Confronting sparse Gaia DR3 photometry with TESS for a sample of around 60,000 OBAF-type pulsators

TL;DR

This study cross-validates Gaia DR3 variable star classifications with TESS data for nearly 60,000 pulsators, confirming Gaia's effectiveness and expanding the catalog of gravity-mode pulsators for future asteroseismic research.

Contribution

It provides a comprehensive reclassification of Gaia pulsators using TESS data and introduces new catalogs with detailed pulsation frequencies and rankings for asteroseismic potential.

Findings

Gaia photometry detects dominant frequencies with ~80% accuracy.

Most Gaia classifications agree with TESS data.

The g-mode pulsator sample forms a continuous main sequence group.

Abstract

The Gaia mission has delivered hundreds of thousands of variable star light curves in multiple wavelengths. Recent work demonstrates that these light curves can be used to identify (non-)radial pulsations in the OBAF-type stars, despite the irregular cadence and low light curve precision of order a few mmag. With the considerably more precise TESS photometry, we revisit these candidate pulsators to conclusively ascertain the nature of their variability. We seek to re-classify the Gaia light curves with the first two years of TESS photometry for a sample of 58,970 p- and g- mode pulsators, encompassing gamma Dor, delta Scuti, SPB, and beta Cep variables. We also supply four new catalogues containing the confirmed pulsators, along with their dominant and secondary pulsation frequencies, the number of independent mode frequencies, and a ranking according to their usefulness for future asteroseismic ensemble analysis. We find that the Gaia photometry is exceptionally accurate for detecting the dominant and secondary frequencies, reaching approximately 80% accuracy in frequency for p- and g-mode pulsators. The majority of Gaia classifications are consistent with the classifications from the TESS data, illustrating the power of the low-cadence Gaia photometry for pulsation studies. We find that the sample of g-mode pulsators forms a continuous group of variable stars along the main sequence across B, A, and F spectral types, implying that the mode excitation mechanisms for all these pulsators need to be updated with improved physics. Finally, we provide a rank-ordered table of pulsators according to their asteroseismic potential for follow-up studies. Our catalogue offers a major increase in the number of confirmed gravity-mode pulsators with an identified dominant mode suitable for follow-up TESS ensemble asteroseismology of such stars.