Exploring Long-period Architectures: Four New Planet Candidates from Kepler with Periods >342 days
2026-08-24 • Machine Learning
Machine Learning
AI summaryⓘ
The authors note that the Kepler telescope usually finds planets that orbit their stars quickly, but often misses planets with longer orbits. They created a new system using artificial intelligence to find these long-orbit planets by detecting single or few transit events. Applying this method, they discovered four new planet candidates with longer orbits than previously found around stars that already have planets causing timing variations. Some candidates had two detected transits, while others had just one, and more observations are needed to confirm and understand these planets. The new planets alone can't explain the timing changes seen in the inner planets, suggesting more planets or factors are involved.
Kepler missiontransit methodorbital periodconvolutional neural networktransit timing variations (TTVs)single transit detectionexoplanet candidatesplanetary radiifollow-up observationsexoplanet system architecture
Authors
Matthew T. Hansen, Jason A. Dittmann
Abstract
The Kepler detection pipeline, as well as the transit method, has a bias towards shorter periods, leaving a dearth of detections at longer orbital periods. This relative lack of detections has left an incomplete picture of the architectures of exoplanet systems within the long-period regime. We have built a single transit detection pipeline, utilizing a classification convolutional neural network and the onboard spacecraft diagnostics of the Kepler spacecraft, to detect long-period planets. We apply our pipeline to all currently known planetary systems in the Kepler field hosting at least one planet with an orbital period longer than 6 days. We manually vet all new signals from our pipeline, and identify four new planetary candidates, all of which are in systems where the inner planets exhibit transit timing variations (TTVs). Two of these candidates, Kepler 1752.02 and Kepler 199.03, cause two transit events that are consistent with periods of $777.78^{+0.01}_{-0.02}$ and $505.495^{+0.004}_{-0.004}$ days, and radii of $3.55^{+0.15}_{-0.15}$ and $2.74^{+0.05}_{-0.05}$ $R_{\oplus}$, respectively. Our remaining two candidates, Kepler 1897.02 and Kepler 1811.02, are single transit candidates with radii $4.81^{+0.20}_{-0.19}$ and $3.25^{+0.28}_{-0.30}$ $R_{\oplus}$, respectively. The shortest orbital periods for these candidates, consistent with the Kepler dataset (gaps and coverage), are 342 days for Kepler 1897.02 and 544 days for Kepler 1811.02. The new planetary candidates, on their own, are incapable of reproducing the observed TTV signals in the inner system. Although difficult to schedule, follow-up observations are needed to further constrain the new candidates and potentially discover the planets causing the perturbations.