Planet Candidates from K2 Campaigns 5-8 and Follow-Up Optical Spectroscopy

TL;DR

This paper reports the discovery of 151 planet candidates from K2 campaigns 5-8, with follow-up spectroscopy improving stellar and planet property estimates, providing a valuable catalog for future confirmation and study.

Contribution

It presents a systematic search for planet candidates in K2 data and incorporates follow-up spectroscopy to refine stellar and planetary parameters, enhancing the accuracy of the candidate catalog.

Findings

151 planet candidates identified from K2 data

Spectroscopy improves host star radius measurements to 10% accuracy

Catalog serves as a foundation for future confirmation efforts

Abstract

We present 151 planet candidates orbiting 141 stars from K2 campaigns 5-8 (C5-C8), identified through a systematic search of K2 photometry. In addition, we identify 16 targets as likely eclipsing binaries, based on their light curve morphology. We obtained follow-up optical spectra of 105/141 candidate host stars and 8/16 eclipsing binaries to improve stellar properties and to identify spectroscopic binaries. Importantly, spectroscopy enables measurements of host star radii with $\approx$10% precision, compared to $\approx$40% precision when only broadband photometry is available. The improved stellar radii enable improved planet radii. Our curated catalog of planet candidates provides a starting point for future efforts to confirm and characterize K2 discoveries.