Luminaries in the sky: The TESS legacy sample of bright stars

I. Asteroseismic detections in naked-eye main-sequence and subgiant solar-like oscillators

¹ Stellar Astrophysics Centre, Department of Physics and Astronomy, Aarhus University, Ny Munkegade 120, 8000 Aarhus C, Denmark
² Department of Astrophysical Sciences, Princeton University, 4 Ivy Lane, Princeton, NJ 08540, USA
³ Instituto de Astrofísica de Canarias (IAC), 38205 La Laguna, Tenerife, Spain
⁴ Universidad de La Laguna (ULL), Departamento de Astrofísica, 38206 La Laguna, Tenerife, Spain
⁵ Université Paris-Saclay, Université Paris Cité, CEA, CNRS, AIM, 91191 Gif-sur-Yvette, France
⁶ Institute for Astronomy, University of Hawai’i, 2680 Woodlawn Drive, Honolulu, HI 96822, USA
⁷ Sydney Institute for Astronomy (SIfA), School of Physics, University of Sydney, NSW 2006, Australia
⁸ Department of Astronomy & Astrophysics, University of Chicago, Chicago, IL 60637, USA
⁹ Department of Physics and Kavli Institute for Astrophysics and Space Research, Massachusetts Institute of Technology, 77 Massachusetts Ave, Cambridge, MA 02139, USA

^★ Corresponding author: mikkelnl@phys.au.dk

Received: 12 May 2025
Accepted: 15 July 2025

Abstract

Aims. We aim to detect and characterise solar-like oscillations in bright naked-eye (V<6) main-sequence and subgiant stars observed by the Transiting Exoplanet Survey Satellite (TESS). In doing so, we seek to expand the current benchmark sample of oscillators, provide accurate global asteroseismic parameters for these bright targets, and assess their potential for future detailed investigations – including missions such as the Habitable Worlds Observatory (HWO) and PLAnetary Transits and Oscillations of stars (PLATO).

Methods. Our sample of bright stars was selected from the Hipparcos/Tycho catalogues. We analysed TESS photometry from both 120-s and 20-s cadences using the standard TESS Science Processing Operations Center (SPOC) light curves and custom apertures extracted from target pixel files. After applying a filtering of the light curves, we extracted global asteroseismic parameters (ν_max and Δν) using the pySYD pipeline. Results were cross-validated with independent pipelines and compared to predictions from the Asteroseismic Target List (ATL), while noise properties were evaluated to quantify improvements from a 20-s observing cadence.

Results. We detect solar-like oscillations in a total of 196 stars – including 128 new detections – with extracted ν_max and Δν values showing strong conformity to expected scaling relations. This corresponds to an increase by more than an order of magnitude in the number of main-sequence stars with detection of solar-like oscillations from TESS. Importantly, our sample of newly detected solar-like oscillators includes nearly 40% of the prime targets for HWO, paving the way for a systematic determination of asteroseismic ages that will be important for the possible interpretation of atmospheric biosignatures. Our analysis confirms that 20-s cadence data yields lower high-frequency noise levels compared to 120-s data. Moreover, the precise stellar parameters obtained through asteroseismology establish these bright stars as benchmarks for seismic investigations and provide useful constraints for refining stellar evolution models and for complementary analyses in interferometry, spectroscopy, and exoplanet characterisation.