Voyager 1 at the speed it moved outward over the year to 2026-10-25 (JPL Horizons). Driving: nonstop, never refuelling.
How it was found
First planet found in 2014, by transit and radial velocity (NASA Exoplanet Archive).
Its planets
Kepler-100 c — 2.2 times Earth's width, a 'sub-Neptune' — bigger than Earth, smaller than Neptune; its year lasts 13 days; about 670 °C, hotter than boiling water; found in 2014 by transit.
Kepler-100 b — 1.3 times Earth's width, about Earth-sized — probably rocky; its year lasts 7 days; about 880 °C, hotter than boiling water; found in 2014 by transit.
Kepler-100 e — 5.3 times Earth's width (estimated from its mass, not measured), Neptune-sized; its year lasts 61 days; about 350 °C, hotter than boiling water; found in 2023 by radial velocity.
Kepler-100 d — 1.6 times Earth's width, a 'sub-Neptune' — bigger than Earth, smaller than Neptune; its year lasts 35 days; about 400 °C, hotter than boiling water; found in 2014 by transit.
NASA Exoplanet Archive, Planetary Systems Composite Parameters (fetched 2026-11-02). Composite values: where a planet's size or mass was not measured, the archive estimates it from the other.
This research has made use of the NASA Exoplanet Archive, which is operated by the California Institute of Technology, under contract with NASA under the Exoplanet Exploration Program.