English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Tools annual

Global: Zendy Free Plan

Global: Zendy Tools monthly

Global: Zendy Plus monthly

Kepler and Hubble photometry of a total of four transits by the Jupiter-sizedKepler-1625b have recently been interpreted to show evidence of a Neptune-sizedexomoon. The profound implications of this first possible exomoon detection andthe physical oddity of the proposed moon, that is, its giant radius prompt usto re-examine the data and the Bayesian Information Criterion (BIC) used fordetection. We combine the Kepler data with the previously published Hubblelight curve. In an alternative approach, we perform a synchronous polynomialdetrending and fitting of the Kepler data combined with our own extraction ofthe Hubble photometry. We generate five million MCMC realizations of the datawith both a planet-only model and a planet-moon model and compute the BICdifference (DeltaBIC) between the most likely models, respectively. DeltaBICvalues of -44.5 (using previously published Hubble data) and -31.0 (using ourown detrending) yield strongly support the exomoon interpretation. Most of ourorbital realizations, however, are very different from the best-fit solutions,suggesting that the likelihood function that best describes the data isnon-Gaussian. We measure a 73.7min early arrival of Kepler-1625b for its Hubbletransit at the 3 sigma level, possibly caused by a 1 day data gap near thefirst Kepler transit, stellar activity, or unknown systematics. The radialvelocity amplitude of a possible unseen hot Jupiter causing Kepler-1625b'stransit timing variation could be some 100m/s. Although we find a similarsolution to the planet-moon model as previously proposed, careful considerationof its statistical evidence leads us to believe that this is not a secureexomoon detection. Unknown systematic errors in the Kepler/Hubble data make theDeltaBIC an unreliable metric for an exomoon search around Kepler-1625b,allowing for alternative interpretations of the signal.

An alternative interpretation of the exomoon candidate signal in the combined Kepler and Hubble data of Kepler-1625