The star
The star
Kepler-123
- Type
- white star
- Surface
- ≈ 6,089 K
- Size
- 1.26 × the Sun
- Mass
- 1.08 × the Sun
- Brightness
- 2.57 × the Sun
- Habitable zone
- 1.18–2.76 AU
The planets
Kepler-123
Kepler-123 b
- Year
- 17.23 days
- Distance from star
- 0.135 AU
- Mass
- 55 Earths
- Size
- 2.9 × Earth
- Temperature
- ≈ 817 K (+544 °C)
- Found
- 2014, transit (Kepler)
Kepler-123
Kepler-123 c
- Year
- 26.70 days
- Distance from star
- 0.181 AU
- Mass
- 2.8 Earths
- Size
- 1.5 × Earth
- Temperature
- ≈ 706 K (+433 °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.