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 Kepler and the Hubble Space Telescope 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 {χ }ν 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, 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 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.
- Publication:
-
The Astrophysical Journal
- Pub Date:
- June 2019
- DOI:
- 10.3847/2041-8213/ab20c8
- arXiv:
- arXiv:1904.10618
- Bibcode:
- 2019ApJ...877L..15K
- Keywords:
-
- planetary systems;
- Astrophysics - Earth and Planetary Astrophysics
- E-Print:
- 7 pages, 5 figures, accepted to ApJL