Peakbagging the K2 KEYSTONE sample with PBjam: characterising the individual mode frequencies in solar-like oscillators

TL;DR

This paper analyzes individual mode frequencies in solar-like oscillators from the K2 KEYSTONE sample using peakbagging with PBjam, significantly expanding mode detections and improving stellar property measurements.

Contribution

It presents the first detailed mode analysis for K2 KEYSTONE stars, demonstrating PBjam's effectiveness and providing extensive mode data for stellar modeling.

Findings

Over 6000 mode frequencies identified across 168 stars

Sample-wide trends in oscillation patterns as a function of stellar properties

Enhanced precision of global asteroseismic parameters

Abstract

The pattern of individual mode frequencies in solar-like oscillators provides valuable insight into their properties and interior structures. The identification and characterisation of these modes requires high signal-to-noise and frequency resolution. The KEYSTONE project unlocks the asteroseismic potential of the K2 mission by providing individually reduced, high-quality time series data, global asteroseismic parameters, and spectroscopic analysis for 173 solar-like oscillators. In this work, we build on the KEYSTONE project and present the first analysis of the pattern of individual modes in the oscillation spectra for the K2 KEYSTONE stars. We perform a robust identification and characterisation of the modes through peakbagging methods in the open-source analysis tool PBjam. We present over 6000 mode frequencies, widths, and heights for 168 stars in the sample, covering the HR diagram from FGK dwarfs to sub-giants and the lower red giant branch, providing a significant increase in the number of individual mode frequency detections for main sequence and sub-giant oscillators. This study also presents sample-wide trends of oscillation patterns as a function of the fundamental stellar properties, and improves the precision of the global asteroseismic parameters. These measurements are part of the legacy of the K2 mission, and can be used to perform detailed modelling to improve the precision of fundamental properties of these stars. The results of this analysis provides evidence for the validity of using PBjam to identify and characterise the modes resulting from the observations of the future PLATO mission.