The authors acknowledge the dedicated teams behind the Kepler and K2 missions, without whom this work would not have been possible. Short-cadence data were obtained through the Cycle 1-6 K2 Guest observer program (GO Program IDs: 1038, 2023, 3023, 4074, 5074, 6039, 7039, 8002, 10002, 11012, 12012, 13012, 14010, 15010, 16010, 17036, 18036, 19036), and associated NASA grants NNS16AE65G, NNX17AL49G, 80NSSC18K0363, and 80NSSC19K0102 to SB. Funding for the Stellar Astrophysics Centre is provided by The Danish National Research Foundation (Grant agreement no.: DNRF106). M.N.L. acknowledges the support of the ESA PRODEX program. D.H. acknowledges support from the Alfred P. Sloan Foundation and the Australian Research Council (FT200100871). S.H. acknowledges support from the European Research Council via the ERC consolidator grant ‘DipolarSound’ (grant agreement #101000296). T.L.C. is supported by Fun-dação para a Ciência e a Tecnologia (FCT) in the form of a work contract (CEECIND/00476/2018). A.M.S. acknowledges grants Spanish program Unidad de Excelencia Mar ía de Maeztu CEX2020-001058-M, 2021-SGR-1526 (Generalitat de Catalunya), and support from ChETEC-INFRA (EU project no. 101008324). A.S. acknowledges support from the European Research Council Consolidator Grant funding scheme (project ASTEROCHRONOMETRY, G.A. n. 772293, http://www.asterochronometry.eu). D.S. is supported by the Australian Research Council (DP190100666). This work has made use of data from the European Space Agency (ESA) mission Gaia (https://www.cosmos.esa.int/gaia), processed by the Gaia Data Processing and Analysis Consortium (DPAC, https://www.cosmos.esa.int/web/gaia/dpac/consortium). Funding for the DPAC has been provided by national institutions, in particular, the institutions participating in the Gaia Multilateral Agreement. We acknowledge the use of the following Python-based software modules: Astropy (Astropy Collaboration 2013), PyAstronomy (Czesla et al. 2019), Lightkurve (Vinícius et al. 2018), Emcee (Foreman-Mackey et al. 2013), PyMC3 (Salvatier et al. 2016), KDEpy (Odland 2018), NumPyro (Phan et al. 2019; Bingham et al. 2019).

[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 Teff and those obtained from the IRFM demonstrates excellent agreement. The iterative approach to spectroscopic analysis significantly enhances the accuracy of the stellar properties derived.

[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.

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

Full Tables 2–4 are available at the CDS via anonymous ftp to cdsarc.cds.unistra.fr (130.79.128.5) or via https://cdsarc.cds.unistra.fr/viz-bin/cat/J/A+A/688/A13

With funding from the Spanish government through the "María de Maeztu Unit of Excellence" accreditation (CEX2020-001058-M)

Mikkel N. Lund et al.

Peer reviewed