Voyager 1 at the speed it moved outward over the year to 2026-10-25 (JPL Horizons). Driving: nonstop, never refuelling.
Facts
HD 4203 b has an equilibrium temperature between −50 and +50 °C.
How it was found
First planet found in 2001, by radial velocity (NASA Exoplanet Archive).
Its planets
HD 4203 c — 13 times Earth's width (estimated from its mass, not measured), a giant, Jupiter-sized or more; its year lasts about 18 Earth years; about −150 °C, below freezing; found in 2014 by radial velocity.
HD 4203 b — 13 times Earth's width (estimated from its mass, not measured), a giant, Jupiter-sized or more; its year lasts 430 days; about 24 °C, between freezing and boiling; found in 2001 by radial velocity.
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.