The Kepler-18 System
Kepler-18 is a planetary system in the constellation Cygnus hosting 3 confirmed exoplanets, about 1,412 light-years from Earth.
Size Comparison: The Planets of Kepler-18
Kepler-18: Star and Habitable Zone
Kepler-18
- Surface temperature
- 5,345 K (Sun: 5,772 K)
- Mass
- 0.97 M☉
- Radius
- 1.11 R☉
- Luminosity
- 0.9311 L☉
- Age
- 10.0 billion years (Sun: 4.6)
Habitable zone of Kepler-18: 0.743–1.772 AU (conservative: 0.940–1.680 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 3 Planets in the Kepler-18 System
| Planet | Type | Orbit | Radius | ESI | Discovered |
|---|---|---|---|---|---|
| Kepler-18 b | Super Earth | 3.5 d | 2.00 R⊕ | 0.26 | 2011 |
| Kepler-18 c | Neptune-like | 7.6 d | 5.49 R⊕ | 0.15 | 2011 |
| Kepler-18 d | Cold Gas Giant | 15 d | 6.98 R⊕ | 0.13 | 2011 |
Discovery History
The first planet found here, Kepler-18 b, was discovered in 2011 using the transit method.
- 2011 — Kepler-18 b (Transit)
- 2011 — Kepler-18 c (Transit)
- 2011 — Kepler-18 d (Transit)
Frequently Asked Questions About Kepler-18
How many planets does Kepler-18 have?
Kepler-18 has 3 confirmed exoplanets. More may await discovery.
Are any planets in the Kepler-18 system habitable?
None of the known planets in Kepler-18 orbit within the star's habitable zone.
How far away is Kepler-18?
Kepler-18 is about 1,412 light-years from Earth in the constellation Cygnus.
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