The K2 Asteroseismic KEYSTONE sample of Dwarf and Subgiant Solar-Like Oscillators. I: Data and Asteroseismic parameters

TL;DR

This paper presents a comprehensive catalogue of asteroseismic parameters for 173 solar-like stars observed by K2, combining spectroscopic, astrometric, and seismic data to improve stellar characterization and identify new oscillation detections.

Contribution

It introduces a new, homogeneous dataset of stellar parameters and seismic detections for dwarfs and subgiants, utilizing an iterative analysis approach for enhanced accuracy.

Findings

Detected solar-like oscillations in 159 stars.

Achieved excellent agreement between spectroscopic and IRFM temperatures.

Improved stellar parameter accuracy through iterative spectroscopic analysis.

Abstract

The KEYSTONE project aims to enhance our understanding of solar-like oscillators by delivering a catalogue of global asteroseismic parameters (${\Delta\nu}$ and ${\nu_{\rm max}}$) for 173 stars, comprising mainly dwarfs and subgiants, observed by the K2 mission in its short-cadence mode during campaigns 6-19. We derive atmospheric parameters and luminosities using spectroscopic data from TRES, astrometric data from $\textit{Gaia}$, 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. 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 ${T_{\rm eff}}$ and those obtained from the IRFM demonstrates excellent agreement. The iterative approach to spectroscopic analysis significantly enhances the accuracy of the stellar properties derived.