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 transit timing variations (NASA Exoplanet Archive).
Its planets
Kepler-247 d — 4.5 times Earth's width, Neptune-sized; its year lasts 20 days; about 260 °C, hotter than boiling water; found in 2014 by transit.
Kepler-247 c — 4.1 times Earth's width, Neptune-sized; its year lasts 9 days; about 410 °C, hotter than boiling water; found in 2014 by transit.
KOI-884 e — 9.5 times Earth's width (estimated from its mass, not measured), Neptune-sized; its year lasts 31 days; found in 2014 by transit timing variations.
Kepler-247 b — 1.6 times Earth's width, a 'sub-Neptune' — bigger than Earth, smaller than Neptune; its year lasts 3 days; about 700 °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.