Kepler-445 c
Kepler-445 c is a mini-Neptune orbiting the M4 star Kepler-445 in the constellation Cygnus. It lies about 415 light-years from Earth and was discovered in 2015 using the transit method.
How Big Is Kepler-445 c?
Kepler-445 c has a radius of 2.51 times that of Earth.
Is Kepler-445 c in the Habitable Zone?
The position of Kepler-445 c relative to the habitable zone of Kepler-445 cannot be precisely determined from the available orbital data.
Habitable zone of Kepler-445: 0.051–0.136 AU (conservative: 0.065–0.129 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 ›
Orbit and Year Length
A year on Kepler-445 c — one full orbit around Kepler-445 — lasts 4.87 Earth days, shorter than Mercury's 88-day year.
How Was Kepler-445 c Discovered?
Kepler-445 c was discovered in 2015 using the transit method, with observations from Kepler.
The transit method watches a star for the tiny, regular dip in brightness that occurs when a planet crosses in front of it. The depth and timing of these dips reveal the planet's size and orbital period.
How Far Away Is Kepler-445 c?
Kepler-445 c is 414.9 light-years (127.2 parsecs) from Earth. Light arriving here tonight left the planet around the year 1612. A probe traveling at the speed of Voyager 1 — about 17 km/s, the fastest outbound spacecraft ever launched — would need roughly 7,302,240 years to make the journey.
Earth Similarity Index
The Earth Similarity Index (ESI) scores how physically similar a planet is to Earth, from 0 to 1, based on radius, density, escape velocity and surface temperature. Kepler-445 c scores 0.36, ranking #694 of 5,568 planets with a known ESI. For reference, Mars scores about 0.70.
The Host Star: Kepler-445
Kepler-445
- Spectral type
- M4
- Surface temperature
- 3,157 K (Sun: 5,772 K)
- Mass
- 0.18 M☉
- Radius
- 0.21 R☉
The Kepler-445 Planetary System
Kepler-445 c is one of 3 known planets in the Kepler-445 system. Its siblings:
- Kepler-445 b (Super Earth)
- Kepler-445 d (Terrestrial)
Kepler-445 c — Complete Data
| Radius | 2.510 Earth radii (0.220 Jupiter radii) |
|---|---|
| Orbital period | 4.87 days |
| Earth Similarity Index | 0.36 |
| Distance from Earth | 414.9 light-years (127.2 parsecs) |
| Constellation | Cygnus |
| Discovery method | Transit |
| Discovery facility | Kepler |
| Discovery year | 2015 |
Data: NASA Exoplanet Archive, last updated 2025-05-19. Earth Similarity Index: PHL @ UPR Arecibo.
Frequently Asked Questions About Kepler-445 c
Is Kepler-445 c habitable?
Kepler-445 c is not known to orbit within the habitable zone of Kepler-445, and as a mini-Neptune it is an unlikely candidate for life as we know it.
How far away is Kepler-445 c?
Kepler-445 c is about 415 light-years from Earth in the constellation Cygnus. A spacecraft traveling as fast as Voyager 1 (about 17 km/s) would need roughly 7,302,240 years to get there.
How big is Kepler-445 c compared to Earth?
Kepler-445 c has 2.51 times the radius of Earth.
How long is a year on Kepler-445 c?
One orbit around Kepler-445 takes 4.9 Earth days — short enough that 75 of its years would fit into one Earth year.
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