Voyager 1 at the speed it moved outward over the year to 2026-10-25 (JPL Horizons). Driving: nonstop, never refuelling.
Facts
HIP 41378 f has an equilibrium temperature between −50 and +50 °C.
How it was found
First planet found in 2016, by transit and radial velocity (NASA Exoplanet Archive).
Its planets
HIP 41378 b — 2.6 times Earth's width, a 'sub-Neptune' — bigger than Earth, smaller than Neptune; its year lasts 16 days; about 690 °C, hotter than boiling water; found in 2016 by transit.
HIP 41378 c — 2.7 times Earth's width, a 'sub-Neptune' — bigger than Earth, smaller than Neptune; its year lasts 32 days; about 480 °C, hotter than boiling water; found in 2016 by transit.
HIP 41378 d — 3.7 times Earth's width, a 'sub-Neptune' — bigger than Earth, smaller than Neptune; its year lasts 280 days; about 94 °C, between freezing and boiling; found in 2016 by transit.
HIP 41378 e — 5.2 times Earth's width, Neptune-sized; its year lasts 390 days; about 62 °C, between freezing and boiling; found in 2016 by transit.
HIP 41378 f — 9.5 times Earth's width, Neptune-sized; its year lasts 540 days; about 21 °C, between freezing and boiling; found in 2016 by transit.
HIP 41378 g — 2.5 times Earth's width (estimated from its mass, not measured), a 'sub-Neptune' — bigger than Earth, smaller than Neptune; its year lasts 63 days; about 330 °C, hotter than boiling water; found in 2025 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.