# Towards Detection of Exoplanetary Rings Via Transit Photometry: Methodology and a Possible Candidate

## TL;DR

This paper develops a systematic method to detect exoplanetary rings via transit photometry and applies it to Kepler data, identifying a promising candidate and setting constraints on ring sizes.

## Contribution

It introduces a novel integration scheme for modeling ringed planet transits and applies it to real data, finding potential ringed exoplanets.

## Key findings

- Six systems inconsistent with large rings beyond 1.5 times planetary radius.
- Identification of five candidate systems with ring-like features.
- KIC 10403228 as a plausible ringed planet candidate.

## Abstract

Detection of a planetary ring of exoplanets remains as one of the most attractive but challenging goals in the field. We present a methodology of a systematic search for exoplanetary rings via transit photometry of long-period planets. The methodology relies on a precise integration scheme we develop to compute a transit light curve of a ringed planet. We apply the methodology to 89 long-period planet candidates from the Kepler data so as to estimate, and/or set upper limits on, the parameters of possible rings. While a majority of our samples do not have a sufficiently good signal-to-noise ratio for meaningful constraints on ring parameters, we find that six systems with a higher signal-to-noise ratio are inconsistent with the presence of a ring larger than 1.5 times the planetary radius assuming a grazing orbit and a tilted ring. Furthermore, we identify five preliminary candidate systems whose light curves exhibit ring-like features. After removing four false positives due to the contamination from nearby stars, we identify KIC 10403228 as a reasonable candidate for a ringed planet. A systematic parameter fit of its light curve with a ringed planet model indicates two possible solutions corresponding to a Saturn-like planet with a tilted ring. There also remain other two possible scenarios accounting for the data; a circumstellar disk and a hierarchical triple. Due to large uncertain factors, we cannot choose one specific model among the three.