The Kepler-138 System
Kepler-138 is a planetary system in the constellation Lyra hosting 4 confirmed exoplanets, about 218 light-years from Earth.
Size Comparison: The Planets of Kepler-138
Planets without a measured radius are not shown.
Kepler-138: Star and Habitable Zone
Kepler-138
- Surface temperature
- 3,841 K (Sun: 5,772 K)
- Mass
- 0.54 M☉
- Radius
- 0.54 R☉
- Luminosity
- 0.0560 L☉
Habitable zone of Kepler-138: 0.193–0.491 AU (conservative: 0.244–0.466 AU), per Kopparapu et al. (2014). Earth orbits the Sun at 1 AU.
See the full interactive habitable-zone view in the Exoplanet Explorer app ›
All 4 Planets in the Kepler-138 System
| Planet | Type | Orbit | Radius | ESI | Discovered |
|---|---|---|---|---|---|
| Kepler-138 b | Terrestrial | 10 d | 0.64 R⊕ | 0.40 | 2014 |
| Kepler-138 c | Super Earth | 14 d | 1.51 R⊕ | 0.46 | 2014 |
| Kepler-138 d | Super Earth | 23 d | 1.51 R⊕ | 0.59 | 2014 |
| Kepler-138 e | Terrestrial | 38 d | — | 0.79 | 2022 |
Discovery History
The first planet found here, Kepler-138 b, was discovered in 2014 using the transit method. The most recent addition, Kepler-138 e, followed in 2022.
- 2014 — Kepler-138 b (Transit)
- 2014 — Kepler-138 c (Transit)
- 2014 — Kepler-138 d (Transit)
- 2022 — Kepler-138 e (Transit Timing Variations)
Frequently Asked Questions About Kepler-138
How many planets does Kepler-138 have?
Kepler-138 has 4 confirmed exoplanets. More may await discovery.
Are any planets in the Kepler-138 system habitable?
None of the known planets in Kepler-138 orbit within the star's habitable zone.
How far away is Kepler-138?
Kepler-138 is about 218 light-years from Earth in the constellation Lyra.
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