An Exomoon Survey of 70 Cool Giant Exoplanets and the New Candidate Kepler-1708 b-i

Abstract

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.

115 pages, 24 figures, 4 tables. Published in Nature Astronomy. Posteriors available at https://doi.org/10.5061/dryad.18931zcz9

References in corpus (29)

• The Dartmouth Stellar Evolution Database
• Seven temperate terrestrial planets around the nearby ultracool dwarf star TRAPPIST-1
• Transit timing effects due to an exomoon
• Alignment of the stellar spin with the orbits of a three-planet system
• Challenges in Planet Formation
• The Photoeccentric Effect and Proto-Hot Jupiters I. Measuring photometric eccentricities of individual transiting planets
• Effects of Orbital Eccentricity on Extrasolar Planet Transit Detection and Lightcurves
• Formation, Habitability, and Detection of Extrasolar Moons
• HEK VI: On the Dearth of Galilean Analogs in Kepler and the Exomoon Candidate Kepler-1625b I
• Impact of Orbital Eccentricity on the Detection of Transiting Extrasolar Planets
• The population of long-period transiting exoplanets
• Transiting planets - lightcurve analysis for eccentric orbits
• spotrod: a semi-analytic model for transits of spotted stars
• No Evidence for Lunar Transit in New Analysis of Hubble Space Telescope Observations of the Kepler-1625 System
• A novel method for identifying exoplanetary rings
• Bayesian priors for the eccentricity of transiting planets
• Detecting extrasolar moons akin to solar system satellites with an orbital sampling effect
• Predicting the Yields of Photometric Surveys for Transiting Extrasolar Planets
• An alternative interpretation of the exomoon candidate signal in the combined Kepler and Hubble data of Kepler-1625
• Circumplanetary disks around young giant planets: a comparison between core-accretion and disk instability
• Stellar rotation--planetary orbit period commensurability in the HAT-P-11 system
• Measuring Transit Signal Recovery in the Kepler Pipeline IV: Completeness of the DR25 Planet Candidate catalog
• Know the Planet, Know the Star: Precise Stellar Densities from Kepler Transit Light Curves
• Transiting Planets near the Snow Line from Kepler. I. Catalog
• The Exomoon Corridor: Half of all exomoons exhibit TTV frequencies within a narrow window due to aliasing
• Exploring formation scenarios for the exomoon candidate Kepler 1625b I
• Application of Orbital Stability and Tidal Migration Constraints for Exomoon Candidates
• The Possible Moon of Kepler-90g is a False Positive
• The Weird Detector: Flagging periodic, coherent signals of arbitrary shape in time series photometry

Cited by in corpus (37)

• Detecting exomoons from radial velocity measurements of self-luminous planets: application to observations of HR 7672 B and future prospects
• Large Exomoons unlikely around Kepler-1625 b and Kepler-1708 b
• The KOBE experiment: K-dwarfs Orbited By habitable Exoplanets. Project goals, target selection and stellar characterization
• Detectability of satellites around directly imaged exoplanets and brown dwarfs
• Measuring the variability of directly imaged exoplanets using vector Apodizing Phase Plates combined with ground-based differential spectrophotometry
• A search for transit timing variations within the exomoon corridor using Kepler data
• Pandora: A fast open-source exomoon transit detection algorithm
• A target list for searching for habitable exomoons
• Stability and detectability of exomoons orbiting HIP 41378 f, a temperate Jovian planet with an anomalously low apparent density
• Detecting Planetary Oblateness in the Era of JWST: A Case Study of Kepler-167e
• Analytic Light Curve for Mutual Transits of Two Bodies Across a Limb-darkened Star
• Kepler-1708 b-i is likely undetectable with HST
• Tidally Heated Exomoons around $\epsilon$ Eridani b: Observability and prospects for characterization
• Delivery of gas onto the circumplanetary disk of giant planets: Planetary-mass dependence of the source region of accreting gas and mass accretion rate
• The bright side of the light curve: a general photometric model of non-transiting exorings
• Direct detectability of tidally heated exomoons by photometric orbital modulation
• Probing Planets with Exomoons: The Cases of Kepler-1708 b and Kepler-1625 b
• The "Drake equation" of exomoons -- a cascade of formation, stability and detection
• Astrometric exomoon detection by means of optical interferometry
• Predictions of the Nancy Grace Roman Space Telescope Galactic Exoplanet Survey. III. Detectability of Giant Exomoons of Wide Separation Giant Planets
• Transit Duration and Timing Variations from Binary Planets
• Exploring Exoplanet Dynamics with JWST: Tides, Rotation, Rings, and Moons
• Capillary processes in extraterrestrial contexts
• Sensitivity to Sub-Io-sized Exosatellite Transits in the MIRI LRS Lightcurve of the Nearest Substellar Worlds
• Survival of satellites during the migration of a Hot Jupiter
• The Dynamics of Co-orbital Giant Exomoons -- Applications for the Kepler-1625 b and Kepler-1708 b Satellite Systems
• Yuti: A General-purpose Transit Simulator for Arbitrary Shaped Objects Orbiting Stars
• The formation of transiting circumplanetary debris discs from the disruption of satellite systems during planet-planet scattering
• Initial conditions for tidal synchronisation of a planet by its moon
• Moon-packing around an Earth-mass Planet
• The CHEOPS view of HD 95338b: refined transit parameters, and a search for exomoons
• GENGA II: GPU planetary N-body simulations with non-Newtonian forces and high number of particles
• Not Just Gas: How Solid-Driven Torques Shaped the Migration of the Galilean Moons
• Parameter estimation from the transit light curve including gravitational lensing effects
• Life in the dark: Potential urability of moons of rogue planets
• The Coupled Tidal Evolution of the Moons and Spins of Warm Exoplanets
• Searching for technosignatures in exoplanetary systems with current and future missions