Kepler-1625 planetary system

Kepler-1625 is a solar-mass star orbited by a Jupiter-sized planet that hosts the first exomoon candidate. If it exists, the exomoon is huge, with a size similar to Neptune. Theoretical considerations suggest that the moon could stably host its own moon, a sub-moon as large as the dwarf planet, Ceres. The relative sizes of the planet, moon and sub-moon, along with their relative distances, orbits and rotation in this model are all based on observational data or theoretical predictions. Due to the scales involved, it is not possible to put the size of the celestial objects on the same scale as their distances. More information: The prospect of moons having moons: https://planetplanet.net/2018/10/09/can-moons-have-moons/