Kepler-22 b

Planet· orbits Kepler-22

Kepler-22 b — the first planet confirmed in the habitable zone of a Sun-like star (2011). At 2.1 Earth radii it is likely a water world or a mini-Neptune rather than a rocky Earth twin, orbiting its Sun-like star every 290 days at a temperate distance. Its size is measured; its mass is only an upper limit, so no density is quoted. Never imaged.

Open in 3D viewSee Kepler-22 b in the live, interactive 3D map

Key facts

Radius

13,379 km

2.1× wider than Earth

Year

290 Earth days

Distance from Kepler-22

0.812 AU

Science

Physical

Radius: 13,379 km · 2.1× wider than Earth

Orbital

Semi-major axis: 0.812 AU; From the NASA Exoplanet Archive (transit + orbit fit)
Eccentricity: 0; From the NASA Exoplanet Archive (transit + orbit fit)
Inclination: 0.00 °; From the NASA Exoplanet Archive (transit + orbit fit)
Orbital period: 289.9 days; From the NASA Exoplanet Archive (transit + orbit fit)
Perihelion: 0.812 AU; Computed from the orbital elements
Aphelion: 0.812 AU; Computed from the orbital elements
Mean orbital velocity: 30.5 km/s; Computed from the orbital elements

Composition

Cloud appearance: Appearance based on NASA/JPL-Caltech's artist's concept. No spacecraft has imaged this world, so its real appearance is unknown — The banded clouds shown are a representation of its class, shown only in Visual mode; Realism shows a plain spectral colour.

Radiation & temperature

Insolation: 1.01 S⊕ · ≈ the sunlight Earth receives; Computed from Kepler-22's luminosity and the orbital distance (inverse-square; Earth's sunlight = 1).

Discovery & history

Discovered: December 5, 2011
Method: Transit detection
Name: Designated 'b' under the IAU convention that letters a star's planets 'b', 'c', 'd'... in the order found (the star is the unwritten 'a'); no IAU proper name has been assigned.

Confirmed in December 2011 as the first Kepler planet squarely in the habitable zone of a Sun-like star — an early milestone toward finding another Earth.

Images

Artist's impression of Kepler-22 b, the first planet confirmed in a Sun-like star's habitable zone (2011) — an artist's concept, not a photograph. — NASA / Ames / JPL-Caltech (public domain) · Wikimedia Commons

NASA's comparison of Kepler's small habitable-zone planets — including Kepler-186 f and Kepler-442 b — with the Solar System (a NASA diagram). — NASA/Ames/JPL-Caltech (public domain) · Wikimedia Commons

Images from open archives · credit shown per image