Kepler-1625b I is a possible moon of exoplanet Kepler-1625b, which may be the first exomoon ever discovered (pending confirmation), and was first indicated after preliminary observations by the Kepler Space Telescope.

[6] The original paper[2] presented two independent lines of evidence for the exomoon, a transit timing variation indicating a Neptune-mass moon, and a photometric dip indicating a Neptune-radius moon.

An independent re-analysis of the observations published in February 2019[7] recovered both but suggested that an inclined and hidden hot-Jupiter could also be responsible, which could be tested with future Doppler spectroscopy radial velocity observations.

A third study analyzing this data set recovered the transit timing variation signature but not the photometric dip, and thus questioned the exomoon hypothesis.

[8] The original discovery team later addressed this paper, finding that their re-reduction exhibits higher systematics that may explain their differing conclusions.