The star
The star
Kepler-122
- Type
- white star
- Surface
- ≈ 6,050 K
- Size
- 1.22 × the Sun
- Mass
- 0.98 × the Sun
- Brightness
- 1.86 × the Sun
- Habitable zone
- 1.01–2.36 AU
The planets
Kepler-122
Kepler-122 b
- Year
- 5.77 days
- Distance from star
- 0.064 AU
- Mass
- 6.1 Earths
- Size
- 2.3 × Earth
- Temperature
- ≈ 1159 K (+886 °C)
- Found
- 2014, transit (Kepler)
Kepler-122
Kepler-122 c
- Year
- 12.47 days
- Distance from star
- 0.108 AU
- Mass
- 29 Earths
- Size
- 5.9 × Earth
- Temperature
- ≈ 897 K (+624 °C)
- Found
- 2014, transit (Kepler)
Kepler-122
Kepler-122 d
- Year
- 21.59 days
- Distance from star
- 0.155 AU
- Mass
- 5.5 Earths
- Size
- 2.2 × Earth
- Temperature
- ≈ 747 K (+474 °C)
- Found
- 2014, transit (Kepler)
Kepler-122
Kepler-122 e
- Year
- 37.99 days
- Distance from star
- 0.227 AU
- Mass
- 28 Earths
- Size
- 2.6 × Earth
- Temperature
- ≈ 618 K (+345 °C)
- Found
- 2014, transit (Kepler)
Kepler-122
Kepler-122 f
- Year
- 56.27 days
- Distance from star
- 0.286 AU
- Mass
- 36 Earths
- Size
- 1.8 × Earth
- Temperature
- ≈ 543 K (+270 °C)
- Found
- 2014, transit (Kepler)
Masses found by the wobble method are minimums, because the orbit's tilt is unknown. Temperatures are equilibrium estimates for a bare planet, before any atmosphere.
How we know
The shadow
The planet passes in front of its star and dims it by a fraction of a percent, every orbit. The dip gives the planet's size and year.
Sources
- Planet and star parameters: NASA Exoplanet Archive, Planetary Systems Composite Parameters, retrieved 1 Nov 2026. 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.
- Position: HYG Database v4.1 (CC BY-SA 4.0).
- Habitable zone: a simple estimate from the star's brightness (√L × 0.95 to 1.67 AU), shown as a guide.