The star
The star
Kepler-222
- Type
- yellow star
- Surface
- ≈ 5,433 K
- Size
- 0.87 × the Sun
- Mass
- 0.93 × the Sun
- Brightness
- 0.459 × the Sun
- Habitable zone
- 0.519–1.24 AU
The planets
Kepler-222
Kepler-222 b
- Year
- 3.94 days
- Distance from star
- 0.048 AU
- Mass
- 10 Earths
- Size
- 3.2 × Earth
- Temperature
- ≈ 1004 K (+731 °C)
- Found
- 2014, transit (Kepler)
Kepler-222
Kepler-222 c
- Year
- 10.09 days
- Distance from star
- 0.091 AU
- Mass
- 19 Earths
- Size
- 4.6 × Earth
- Temperature
- ≈ 734 K (+461 °C)
- Found
- 2014, transit (Kepler)
Kepler-222
Kepler-222 d
- Year
- 28.08 days
- Distance from star
- 0.18 AU
- Mass
- 13 Earths
- Size
- 3.7 × Earth
- Temperature
- ≈ 522 K (+249 °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.