An Exomoon Survey Of 70 Cool Giant Exoplanets And The New Candidate Kepler-1708 b-i

Orbital properties of the 70 cool giants. A comparison of the derived orbital eccentricities from this work (y-axis) versus the orbital periods (previously known) for our planetary candidates sample. We use colour (see legend) to depict the inferred absence/presence of transit timing variations (TTVs).

Exomoons represent a crucial missing puzzle piece in our efforts to understand extrasolar planetary systems.

To address this deficiency, we here describe an exomoon survey of 70 cool, giant transiting exoplanet candidates found by Kepler. We identify only one which exhibits a moon-like signal that passes a battery of vetting tests: Kepler-1708 b. We show that Kepler-1708 b is a statistically validated Jupiter-sized planet orbiting a Sun-like quiescent star at ~1.6AU.

The signal of the exomoon candidate, Kepler-1708 b-i, is a 4.8-sigma effect and is persistent across different instrumental detrending methods, with a 1% false-positive probability via injection-recovery. Kepler-1708 b-i is ~2.6 Earth radii and is located in an approximately coplanar orbit at ~12 planetary radii from its ~1.6AU Jupiter-sized host. Future observations will be necessary to validate or reject the candidate.

David Kipping, Steve Bryson, Chris Burke, Jessie Christiansen, Kevin Hardegree-Ullman, Billy Quarles, Brad Hansen, Judit Szulágyi, Alex Teachey

Comments: 115 pages, 24 figures, 4 tables. Published in Nature Astronomy. Posteriors available at this https URL
Subjects: Earth and Planetary Astrophysics (astro-ph.EP)
DOI: 10.1038/s41550-021-01539-1
Cite as: arXiv:2201.04643 [astro-ph.EP] (or arXiv:2201.04643v1 [astro-ph.EP] for this version)
Submission history
From: David Kipping
[v1] Wed, 12 Jan 2022 19:00:03 UTC (3,740 KB)

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