The K2 Asteroseismic KEYSTONE sample of Dwarf and Subgiant Solar-Like Oscillators

I. Data and Asteroseismic parameters^★

¹ Stellar Astrophysics Centre, Department of Physics and Astronomy, Aarhus University, Ny Munkegade 120, 8000 Aarhus C, Denmark
e-mail: mikkelnl@phys.au.dk
² Department of Astronomy, Yale University, PO Box 208101, New Haven, CT 06520-8101, USA
³ Center for Astrophysics | Harvard-Smithsonian, 60 Garden Street Cambridge, MA 02138, USA
⁴ Research School of Astronomy and Astrophysics, Mount Stromlo Observatory, The Australian National University, ACT 2611, Australia
⁵ Institute for Astronomy, University of Hawai‘i, 2680 Woodlawn Drive, Honolulu, HI 96822, USA
⁶ Sydney Institute for Astronomy (SIfA), School of Physics, University of Sydney, NSW 2006, Australia
⁷ Center for Astronomy (ZAH/LSW), Heidelberg University, Königstuhl 12, 69117 Heidelberg, Germany
⁸ Heidelberger Institut für Theoretische Studien, Schloss-Wolfsbrunnenweg 35, 69118 Heidelberg, Germany
⁹ Max Planck Institute for Solar System Research, Göttingen, Germany
¹⁰ School of Physics and Astronomy, University of Birmingham, Edgbaston, Birmingham B15 2TT, UK
¹¹ Instituto de Astrofísica e Ciências do Espaço, Universidade do Porto, Rua das Estrelas, 4150-762 Porto, Portugal
¹² Departamento de Física e Astronomia, Faculdade de Ciências da Universidade do Porto, Rua do Campo Alegre, s/n, 4169-007 Porto, Portugal
¹³ Institute of Space Sciences (ICE, CSIC) Campus UAB, Carrer de Can Magrans s/n, 08193, Bellaterra, Spain
¹⁴ Institut d’Estudis Espacials de Catalunya (IEEC), C/Gran Capita, 2–4, 08034 Barcelona, Spain
¹⁵ Advanced Research Computing, University of Birmingham, Edgbaston, Birmingham, B15 2TT, UK
¹⁶ Dipartimento di Fisica e Astronomia, Università degli Studi di Bologna, Via Gobetti 93/2, 40129 Bologna, Italy
¹⁷ INAF – Osservatorio di Astrofisica e Scienza dello Spazio di Bologna, Via Gobetti 93/3, 40129 Bologna, Italy
¹⁸ School of Physics, University of New South Wales, NSW 2052, Australia
¹⁹ The Australian Research Council Centre of Excellence for All Sky Astrophysics in 3 Dimensions (ASTRO 3D), Australia
²⁰ Department of Astronomy, Columbia University, 550 West 120th Street, New York, NY, USA
²¹ DARK, Niels Bohr Institute, University of Copenhagen, Jagtvej 128, 2200, Copenhagen, Denmark

Received: 21 March 2024
Accepted: 20 May 2024

Abstract

Aims. The KEYSTONE project aims to enhance our understanding of solar-like oscillators by delivering a catalogue of global asteroseismic parameters (Δv and v_max) for 173 stars, comprising mainly dwarfs and subgiants, observed by the K2 mission in its short-cadence mode during campaigns 6–19.

Methods. We derive atmospheric parameters and luminosities using spectroscopic data from TRES, astrometric data from Gaia, and the infrared flux method (IRFM) for a comprehensive stellar characterisation. Asteroseismic parameters are robustly extracted using three independent methods, complemented by an iterative refinement of the spectroscopic analyses using seismic log g values to enhance parameter accuracy.

Results. Our analysis identifies new detections of solar-like oscillations in 159 stars, providing an important complement to already published results from previous campaigns. The catalogue provides homogeneously derived atmospheric parameters and luminosities for the majority of the sample. Comparison between spectroscopic T_eff and those obtained from the IRFM demonstrates excellent agreement. The iterative approach to spectroscopic analysis significantly enhances the accuracy of the stellar properties derived.