The Kepler-257 System
Kepler-257 is a planetary system in the constellation Cygnus hosting 3 confirmed exoplanets, about 2,545 light-years from Earth.
Size Comparison: The Planets of Kepler-257
Kepler-257: Star and Habitable Zone
Kepler-257
- Surface temperature
- 5,180 K (Sun: 5,772 K)
- Radius
- 1.04 R☉
Habitable zone of Kepler-257: 0.647–1.554 AU (conservative: 0.820–1.473 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-257 System
| Planet | Type | Orbit | Radius | ESI | Discovered |
|---|---|---|---|---|---|
| Kepler-257 b | Mini Neptune | 2.4 d | 2.61 R⊕ | 0.23 | 2014 |
| Kepler-257 c | Neptune-like | 6.6 d | 5.41 R⊕ | 0.15 | 2014 |
| Kepler-257 d | Neptune-like | 25 d | 4.95 R⊕ | 0.22 | 2014 |
Discovery History
The first planet found here, Kepler-257 b, was discovered in 2014 using the transit method.
- 2014 — Kepler-257 b (Transit)
- 2014 — Kepler-257 c (Transit)
- 2014 — Kepler-257 d (Transit)
Frequently Asked Questions About Kepler-257
How many planets does Kepler-257 have?
Kepler-257 has 3 confirmed exoplanets. More may await discovery.
Are any planets in the Kepler-257 system habitable?
None of the known planets in Kepler-257 orbit within the star's habitable zone.
How far away is Kepler-257?
Kepler-257 is about 2,545 light-years from Earth in the constellation Cygnus.
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