K2-138, ein G8-V-Stern, hat 6 bestätigte Planeten.
Gemessen
Entfernung
etwa 661 Lichtjahre
Spektraltyp des Sterns
G8 V
Bestätigte Planeten
6
Entfernung von der Sonne
Über 661 Lichtjahre. Zum Durchqueren:
Licht661 Jahre
Geschwindigkeit von Voyager 111.7 Millionen Jahre
Fahrt mit 100 km/h7.13 Milliarden Jahre
Voyager 1 mit der Geschwindigkeit, mit der sie sich im Jahr bis 2026-10-25 nach außen bewegte (JPL Horizons). Fahrt: ohne Pause, ohne je nachzutanken.
Wie er entdeckt wurde
Erster Planet, entdeckt 2017 durch Transit (NASA Exoplanet Archive).
Seine Planeten
K2-138 c — 2.3 times Earth's width, a 'sub-Neptune' — bigger than Earth, smaller than Neptune; its year lasts 4 days; about 740 °C, hotter than boiling water; found in 2017 by transit.
K2-138 d — 2.4 times Earth's width, a 'sub-Neptune' — bigger than Earth, smaller than Neptune; its year lasts 5 days; about 620 °C, hotter than boiling water; found in 2017 by transit.
K2-138 b — 1.5 times Earth's width, about Earth-sized — probably rocky; its year lasts 2 days; about 880 °C, hotter than boiling water; found in 2017 by transit.
K2-138 e — 3.4 times Earth's width, a 'sub-Neptune' — bigger than Earth, smaller than Neptune; its year lasts 8 days; about 480 °C, hotter than boiling water; found in 2017 by transit.
K2-138 g — 3 times Earth's width, a 'sub-Neptune' — bigger than Earth, smaller than Neptune; its year lasts 42 days; about 170 °C, hotter than boiling water; found in 2021 by transit.
K2-138 f — 2.9 times Earth's width, a 'sub-Neptune' — bigger than Earth, smaller than Neptune; its year lasts 13 days; about 380 °C, hotter than boiling water; found in 2017 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.