The star
The star
Kepler-191
- Type
- orange dwarf
- Surface
- ≈ 5,215 K
- Size
- 0.80 × the Sun
- Mass
- 0.84 × the Sun
- Brightness
- 0.385 × the Sun
- Habitable zone
- 0.481–1.15 AU
The planets
Kepler-191
Kepler-191 d
- Year
- 5.95 days
- Distance from star
- 0.061 AU
- Mass
- 5.8 Earths
- Size
- 2.3 × Earth
- Temperature
- ≈ 857 K (+584 °C)
- Found
- 2016, transit (Kepler)
Kepler-191
Kepler-191 b
- Year
- 9.94 days
- Distance from star
- 0.087 AU
- Mass
- 2.4 Earths
- Size
- 1.3 × Earth
- Temperature
- ≈ 722 K (+449 °C)
- Found
- 2014, transit (Kepler)
Kepler-191
Kepler-191 c
- Year
- 17.74 days
- Distance from star
- 0.128 AU
- Mass
- 4.1 Earths
- Size
- 1.9 × Earth
- Temperature
- ≈ 596 K (+323 °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.