The star
The star
K2-187
- Type
- yellow star
- Surface
- ≈ 5,438 K
- Size
- 0.83 × the Sun
- Mass
- 0.97 × the Sun
- Brightness
- 0.637 × the Sun
- Habitable zone
- 0.611–1.45 AU
The planets
K2-187
K2-187 b
- Year
- 0.77 days
- Distance from star
- 0.0164 AU
- Mass
- 1.9 Earths
- Size
- 1.2 × Earth
- Temperature
- ≈ 1815 K (+1542 °C)
- Found
- 2018, transit (K2)
K2-187
K2-187 c
- Year
- 2.87 days
- Distance from star
- 0.0392 AU
- Mass
- 2.5 Earths
- Size
- 1.4 × Earth
- Temperature
- ≈ 1173 K (+900 °C)
- Found
- 2018, transit (K2)
K2-187
K2-187 d
- Year
- 7.15 days
- Distance from star
- 0.072 AU
- Mass
- 6.3 Earths
- Size
- 2.4 × Earth
- Temperature
- ≈ 865 K (+592 °C)
- Found
- 2018, transit (K2)
K2-187
K2-187 e
- Year
- 13.61 days
- Distance from star
- 0.111 AU
- Mass
- 4.3 Earths
- Size
- 1.9 × Earth
- Temperature
- ≈ 698 K (+425 °C)
- Found
- 2018, transit (K2)
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.