NASA (Exoplanet Catalog artwork)Kepler-22b
The first Kepler planet confirmed in a star's habitable zone
Overview
Kepler-22b is an exoplanet orbiting the Sun-like star Kepler-22 within its habitable zone. It is located about 640 light-years from Earth in the constellation Cygnus. Discovered by NASA's Kepler space telescope, it was announced on 5 December 2011 as the first known transiting planet to orbit within the habitable zone of a Sun-like star, where conditions could allow liquid water to exist on the surface.
Source: Wikipedia
NASA: Kepler-22 b is a super Earth exoplanet that orbits a G-type star. Its mass is 9.1 Earths, it takes 289.9 days to complete one orbit of its star, and is 0.812 AU from its star. Its discovery was announced in 2011.
Why it matters
- Announced in 2011 with a 290-day orbit around a Sun-like star.
- About 2.4 Earth radii — likely a water world or mini-Neptune rather than a rocky planet.
- Its equilibrium temperature is close to Earth's, which made it the first 'Goldilocks' headline.
NASA puts it this way: “A possible ocean world orbiting in the habitable zone—the region around a star where the temperature is right for liquid water, a requirement for life on Earth.”
Discovery & system
- Discovered
- 2011 · Transit · Kepler
- Discovery paper
- Borucki et al. 2012
- Discoverers
- Kepler Space Telescope
- Host star
- Kepler-22 · G5 V · 5,596 K · 0.86 M☉
- System
- 1 known planet
The system
| World | Period | Distance | Radius | Mass | Temp. |
|---|---|---|---|---|---|
| Kepler-22 b | 289.9 d | 0.812 AU | 2.1 R⊕ | 9.1 M⊕ | 279 K |
By the numbers
- Radius
- 2.1 R⊕13,379 km
- Mass
- 9.1 M⊕54.35 ×10²⁴ kg
- Orbital period
- 289.9 d0.79 yr
- Distance from star
- 0.812 AU121 million km
- Eccentricity
- 0.72highly elliptical
- Equilibrium temp.
- 279 K6 °C
- Starlight received
- 1 × Earth
- Distance from Earth
- 635 ly194.6 pc
- Density
- 5.2 g/cm³0.94 × Earth
Sources
Image: NASA (Exoplanet Catalog artwork) · NASA media: generally free of copyright · image page
Text: Wikipedia (CC BY-SA 4.0). Taglines and highlights are editorial.