The star
The star
Kepler-1388
- Type
- orange dwarf
- Surface
- ≈ 4,098 K
- Size
- 0.61 × the Sun
- Mass
- 0.63 × the Sun
- Brightness
- 0.0782 × the Sun
- Habitable zone
- 0.226–0.57 AU
The planets
Kepler-1388
Kepler-1388 c
- Year
- 5.54 days
- Distance from star
- 0.0519 AU
- Mass
- 5.7 Earths
- Size
- 2.3 × Earth
- Temperature
- ≈ 566 K (+293 °C)
- Found
- 2016, transit (Kepler)
Kepler-1388
Kepler-1388 b
- Year
- 12.29 days
- Distance from star
- 0.0882 AU
- Mass
- 7.2 Earths
- Size
- 2.6 × Earth
- Temperature
- ≈ 434 K (+161 °C)
- Found
- 2016, transit (Kepler)
Kepler-1388
Kepler-1388 d
- Year
- 20.96 days
- Distance from star
- 0.126 AU
- Mass
- 8.6 Earths
- Size
- 2.9 × Earth
- Temperature
- ≈ 363 K (+90 °C)
- Found
- 2016, transit (Kepler)
Kepler-1388
Kepler-1388 e
- Year
- 37.63 days
- Distance from star
- 0.186 AU
- Mass
- 6.6 Earths
- Size
- 2.5 × Earth
- Temperature
- ≈ 299 K (+26 °C)
- Found
- 2016, 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.