Detection of Hundreds of New Planet Candidates and Eclipsing Binaries in K2 Campaigns 0-8

TL;DR

This study identifies 818 new exoplanet candidates and 579 eclipsing binaries in K2 data, including multi-planet systems, some potentially habitable, significantly expanding known exoplanets and providing targets for follow-up observations.

Contribution

First comprehensive search in K2 campaigns 0-8 using a modified QATS algorithm, discovering hundreds of new planet candidates and eclipsing binaries, including systems with potential habitability.

Findings

Detected 818 planet candidates, 374 new discoveries.

Identified 579 eclipsing binary systems.

Found candidates with transit timing variations and ultra-short periods.

Abstract

We implement a search for exoplanets in campaigns zero through eight (C0-8) of the K2 extension of the Kepler spacecraft. We apply a modified version of the QATS planet search algorithm to K2 light curves produced by the EVEREST pipeline, carrying out the C0-8 search on $1.5 \times 10^5$ target stars with magnitudes in the range of Kp = 9-15. We detect 818 transiting planet candidates, of which 374 were undiscovered by prior searches, with {64,15,5,2,1} in {2,3,4,5,6}-planet multi-planet candidate systems, respectively. Of the new planets detected, 100 orbit M dwarfs, including one which is potentially rocky and in the habitable zone. 154 of our candidates reciprocally transit with our Solar System: they are geometrically aligned to see at least one Solar System planet transit. We find candidates which display transit timing variations and dozens of candidates on both period extremes with single transits or ultra-short periods. We point to evidence that our candidates display similar patterns in frequency and size-period relation as confirmed planets, such as tentative evidence for the radius gap. Confirmation of these planet candidates with follow-up studies will increase the number of K2 planets by up to 50%, and characterization of their host stars will improve statistical studies of planet properties. Our sample includes many planets orbiting bright stars amenable for radial velocity follow-up and future characterization with JWST. We also list the 579 eclipsing binary systems detected as part of this search.