Luminaries in the Sky: The TESS LEGACY Sample of Bright Stars. II. In-depth seismic characterisation of 32 naked-eye stars in the PLATO LOP fields

TL;DR

This study provides detailed seismic analysis of 32 bright stars in the PLATO fields, aiding calibration and validation of PLATO's asteroseismic capabilities using multiple independent pipelines.

Contribution

It offers the first detailed seismic parameter extraction for 26 stars within the PLATO LOP fields, demonstrating analysis robustness and highlighting the need for longer datasets for some sub-giants.

Findings

Consistent seismic parameter trends across pipelines.

Identification of mixed modes varies among pipelines for sub-giants.

The sample will be crucial for calibrating PLATO's seismic performance.

Abstract

The NASA TESS mission is conducting a nearly full-sky survey, enabling the photometric characterisation of millions of stars. The forthcoming ESA PLATO mission will provide long-duration, high-precision photometry of tens of thousands of bright stars to be characterised through asteroseismology. The TESS Luminaries Sample is a catalogue of 196 bright naked-eye (V < 6) main-sequence (MS) and sub-giant (SG) stars exhibiting solar-like oscillations. Among them, the subset located within the PLATO Long-duration Observation Phase (LOP) fields constitutes an exceptional set of targets that will be observable by PLATO from the earliest phases of the mission, making them ideal calibrators during commissioning and the first months of science operations. This paper aims to provide an in-depth asteroseismic characterisation of 32 Luminaries stars that fall within the PLATO LOP fields of view. Individual mode parameters were extracted for the first time for 26 of them. We used three independent seismic pipelines, one of which is similar to the algorithms used in the official PLATO pipeline. Statistical criterion were applied to identify the optimal combination of data calibration, observing cadence, and fitting pipeline for each star. For all stars, we derived large and small separations, the asymptotic phase term, radial mode amplitudes, and mean linewidths per order. Comparisons reveal consistent trends in the seismic parameters, confirming the robustness of our analysis. In sub-giants, mixed-mode identification differs in the three pipelines, revealing extraction inconsistencies requiring longer datasets to improve our mode identifications. The Luminaries stars located in the PLATO LOP fields constitute a unique sample that will play a crucial role in validating, calibrating, and optimising PLATO's seismic performance.