Evidence for a large exomoon orbiting Kepler-1625b
Publication date: 04 October 2018
Authors: Teachey, A. and Kipping, D.M.
Journal: Science Advances
Volume: 4
Issue: 10
Page: eaav1784
Year: 2018
Copyright: 2018 The Authors, some rights reserved; exclusive licensee AAAS. No claim to original U.S. Government Works. Distributed under a Creative Commons Attribution NonCommercial License 4.0 (CC BY-NC)
Exomoons are the natural satellites of planets orbiting stars outside our solar system, of which there are currently no confirmed examples. We present new observations of a candidate exomoon associated with Kepler-1625b using the Hubble Space Telescope to validate or refute the moon's presence. We find evidence in favor of the moon hypothesis, based on timing deviations and a flux decrement from the star consistent with a large transiting exomoon. Self-consistent photodynamical modeling suggests that the planet is likely several Jupiter masses, while the exomoon has a mass and radius similar to Neptune. Since our inference is dominated by a single but highly precise Hubble epoch, we advocate for future monitoring of the system to check model predictions and confirm repetition of the moon-like signal.
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