The star
The star
Kepler-306
- Type
- orange dwarf
- Surface
- ≈ 4,954 K
- Size
- 0.72 × the Sun
- Mass
- 0.75 × the Sun
- Brightness
- 0.339 × the Sun
- Habitable zone
- 0.457–1.11 AU
The planets
Kepler-306
Kepler-306 b
- Year
- 4.65 days
- Distance from star
- 0.05 AU
- Mass
- 2.9 Earths
- Size
- 1.5 × Earth
- Temperature
- ≈ 830 K (+557 °C)
- Found
- 2014, transit (Kepler)
Kepler-306
Kepler-306 c
- Year
- 7.24 days
- Distance from star
- 0.067 AU
- Mass
- 6.1 Earths
- Size
- 2.4 × Earth
- Temperature
- ≈ 716 K (+443 °C)
- Found
- 2014, transit (Kepler)
Kepler-306
Kepler-306 d
- Year
- 17.33 days
- Distance from star
- 0.12 AU
- Mass
- 6.7 Earths
- Size
- 2.5 × Earth
- Temperature
- ≈ 535 K (+262 °C)
- Found
- 2014, transit (Kepler)
Kepler-306
Kepler-306 e
- Year
- 44.84 days
- Distance from star
- 0.227 AU
- Mass
- 5.8 Earths
- Size
- 2.3 × Earth
- Temperature
- ≈ 390 K (+117 °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.