TFAW survey II: 6 Newly Validated Planets and 13 Planet Candidates from K2

TL;DR

This study re-analyzed K2 data using wavelet-based methods and the TLS algorithm, leading to the validation of six new sub-Neptune-sized planets and identification of 13 additional planet candidates, including ultra-short-period and multi-planet systems.

Contribution

It introduces a novel re-analysis approach for K2 light curves, validating new planets and candidates that were previously undetected, especially around faint stars.

Findings

Validated six new planets with false-positive probability <1%.

Identified 13 additional planet candidates for future follow-up.

Discovered systems with ultra-short-period planets and planets within the small planet Radius Gap.

Abstract

Searching for Earth-sized planets in data from Kepler's extended mission (K2) is a niche that still remains to be fully exploited. The TFAW survey is an ongoing project that aims to re-analyze all light curves in K2 C1-C8 and C12-C18 campaigns with a wavelet-based detrending and denoising method, and the period search algorithm TLS to search for new transit candidates not detected in previous works. We have analyzed a first subset of 24 candidate planetary systems around relatively faint host stars (10.9 < $K_{p}$ < 15.4) to allow for follow-up speckle imaging observations. Using VESPA and TRICERATOPS, we statistically validate six candidates orbiting four unique host stars by obtaining false-positive probabilities smaller than 1% with both methods. We also present 13 vetted planet candidates that might benefit from other, more precise follow-up observations. All of these planets are sub-Neptune-sized, with two validated planets and three candidates with sub-Earth sizes, and have orbital periods between 0.81 and 23.98 days. Some interesting systems include two ultra-short-period planets, three multi-planetary systems, three sub-Neptunes that appear to be within the small planet Radius Gap, and two validated and one candidate sub-Earths (EPIC 210706310, EPIC 210768568, and EPIC 246078343) orbiting metal-poor stars.