No Evidence for Lunar Transit in New Analysis of Hubble Space Telescope Observations of the Kepler-1625 System

Abstract

Observations of the Kepler-1625 system with the Kepler and Hubble Space Telescopes have suggested the presence of a candidate exomoon, Kepler-1625b I, a Neptune-radius satellite orbiting a long-period Jovian planet. Here we present a new analysis of the Hubble observations, using an independent data reduction pipeline. We find that the transit light curve is well fit with a planet-only model, with a best-fit ${\chi }_{\nu }^2$ equal to 1.01. The addition of a moon does not significantly improve the fit quality. We compare our results directly with the original light curve from Teachey & Kipping (2018), and find that we obtain a better fit to the data using a model with fewer free parameters (no moon). We discuss possible sources for the discrepancy in our results, and conclude that the lunar transit signal found by Teachey & Kipping (2018) was likely an artifact of the data reduction. This finding highlights the need to develop independent pipelines to confirm results that push the limits of measurement precision.

arXiv comment7 pages, 5 figures, accepted to ApJL

References in corpus (29)

• emcee: The MCMC Hammer
• Gaia Data Release 2. Summary of the contents and survey properties
• The Gaia mission
• The Dartmouth Stellar Evolution Database
• REBOUND: An open-source multi-purpose N-body code for collisional dynamics
• Clouds in the atmosphere of the super-Earth exoplanet GJ 1214b
• Infrared Transmission Spectroscopy of the Exoplanets HD209458b and XO-1b Using the Wide Field Camera-3 on the Hubble Space Telescope
• Helium in the eroding atmosphere of an exoplanet
• Transit timing effects due to an exomoon
• Limb darkening and exoplanets: testing stellar model atmospheres and identifying biases in transit parameters
• Hubble Space Telescope Near-IR Transmission Spectroscopy of the Super-Earth HD 97658b
• Transit timing effects due to an exomoon II
• Evidence for a Large Exomoon Orbiting Kepler-1625b
• Formation, Habitability, and Detection of Extrasolar Moons
• HEK VI: On the Dearth of Galilean Analogs in Kepler and the Exomoon Candidate Kepler-1625b I
• The Hunt for Exomoons with Kepler (HEK): II. Analysis of Seven Viable Satellite-Hosting Planet Candidates
• A UBV Photometric Survey of the Kepler Field
• A Physical Model-based Correction for Charge Traps in the Hubble Space Telescope's Wide Field Camera 3 Near-IR Detector and Applications to Transiting Exoplanets and Brown Dwarfs
• On the Direct Imaging of Tidally Heated Exomoons
• On the detection of Exomoons: A search in Kepler data for the orbital sampling effect and the scatter peak
• Detection of Exomoons Through Observation of Radio Emissions
• The Center of Light: Spectroastrometric Detection of Exomoons
• An alternative interpretation of the exomoon candidate signal in the combined Kepler and Hubble data of Kepler-1625
• Predicting Exoplanets Mass and Radius: A Nonparametric Approach
• Methods for exomoon characterisation: combining transit photometry and the Rossiter-McLaughlin effect
• Planet-Planet Occultations in TRAPPIST-1 and Other Exoplanet Systems
• Revisiting the exomoon candidate signal around Kepler-1625b
• Detecting Exomoons Via Doppler Monitoring of Directly Imaged Exoplanets
• Detecting Exomoons Around Self-luminous Giant Exoplanets Through Polarization

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• A Fast, 2D Gaussian Process Method Based on Celerite: Applications to Transiting Exoplanet Discovery and Characterization
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• Large planets may not form fractionally large moons
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