The star
The star
K2-389
- Type
- G3
- Surface
- ≈ 5,773 K
- Size
- 1.09 × the Sun
- Mass
- 0.99 × the Sun
- Brightness
- 1.28 × the Sun
- Habitable zone
- 0.849–2 AU
The planets
K2-389
K2-389 b
- Year
- 8.58 days
- Distance from star
- 0.0818 AU
- Mass
- 6 Earths
- Size
- 2.3 × Earth
- Temperature
- ≈ 932 K (+659 °C)
- Found
- 2022, transit (K2)
K2-389
K2-389 c
- Year
- 20.85 days
- Distance from star
- 0.148 AU
- Mass
- 4.8 Earths
- Size
- 2 × Earth
- Found
- 2022, 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.