A Search for Exozodiacal Clouds with Kepler

TL;DR

This study searched for resonant exozodiacal dust structures caused by hot Jupiters in Kepler data, finding no confirmed structures and setting upper limits on their occurrence frequency, which informs planetary system evolution models.

Contribution

First search for resonant exozodiacal dust structures in Kepler data, establishing upper limits on their frequency around hot Jupiters and demonstrating the rarity of such features.

Findings

No confirmed exozodiacal structures detected.

Less than 21% of hot Jupiters have dense resonant dust clumps.

Detected candidate was a false positive, not a real dust structure.

Abstract

Planets embedded within dust disks may drive the formation of large scale clumpy dust structures by trapping dust into resonant orbits. Detection and subsequent modeling of the dust structures would help constrain the mass and orbit of the planet and the disk architecture, give clues to the history of the planetary system, and provide a statistical estimate of disk asymmetry for future exoEarth-imaging missions. Here we present the first search for these resonant structures in the inner regions of planetary systems by analyzing the light curves of hot Jupiter planetary candidates identified by the Kepler mission. We detect only one candidate disk structure associated with KOI 838.01 at the 3-sigma confidence level, but subsequent radial velocity measurements reveal that KOI 838.01 is a grazing eclipsing binary and the candidate disk structure is a false positive. Using our null result, we place an upper limit on the frequency of dense exozodi structures created by hot Jupiters. We find that at the 90% confidence level, less than 21% of Kepler hot Jupiters create resonant dust clumps that lead and trail the planet by ~90 degrees with optical depths >~5*10^-6, which corresponds to the resonant structure expected for a lone hot Jupiter perturbing a dynamically cold dust disk 50 times as dense as the zodiacal cloud.