Voyager 1 at the speed it moved outward over the year to 2026-10-25 (JPL Horizons). Driving: nonstop, never refuelling.
Facts
HN Lib b has an equilibrium temperature between −50 and +50 °C.
How it was found
First planet found in 2023, by radial velocity (NASA Exoplanet Archive).
Its planets
HN Lib b — 2.2 times Earth's width (estimated from its mass, not measured), a 'sub-Neptune' — bigger than Earth, smaller than Neptune; its year lasts 36 days; about −39 °C, below freezing; found in 2023 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.