Kepler-561 c
Kepler-561 c is a mini-Neptune orbiting Kepler-561 in the constellation Cygnus. It lies about 2,027 light-years from Earth and was discovered in 2016 using the transit method.
How Big Is Kepler-561 c?
Kepler-561 c has a radius of 2.68 times that of Earth.
Is Kepler-561 c in the Habitable Zone?
The position of Kepler-561 c relative to the habitable zone of Kepler-561 cannot be precisely determined from the available orbital data.
Habitable zone of Kepler-561: 0.679–1.605 AU (conservative: 0.860–1.522 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-561 c — one full orbit around Kepler-561 — lasts 5.35 Earth days, shorter than Mercury's 88-day year.
How Was Kepler-561 c Discovered?
Kepler-561 c was discovered in 2016 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-561 c?
Kepler-561 c is 2,026.7 light-years (621.4 parsecs) from Earth. Light arriving here tonight left the planet about 2,027 years ago. A probe traveling at the speed of Voyager 1 — about 17 km/s, the fastest outbound spacecraft ever launched — would need roughly 35,669,920 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-561 c scores 0.23, ranking #3,520 of 5,568 planets with a known ESI. For reference, Mars scores about 0.70.
The Host Star: Kepler-561
Kepler-561
- Surface temperature
- 5,646 K (Sun: 5,772 K)
- Mass
- 0.96 M☉
- Radius
- 0.94 R☉
- Age
- 4.3 billion years (Sun: 4.6)
The Kepler-561 Planetary System
Kepler-561 c is one of 2 known planets in the Kepler-561 system. Its siblings:
- Kepler-561 b (Cold Gas Giant)
Kepler-561 c — Complete Data
| Radius | 2.680 Earth radii (0.239 Jupiter radii) |
|---|---|
| Orbital period | 5.35 days |
| Earth Similarity Index | 0.23 |
| Distance from Earth | 2,026.7 light-years (621.4 parsecs) |
| Constellation | Cygnus |
| Discovery method | Transit |
| Discovery facility | Kepler |
| Discovery year | 2016 |
Data: NASA Exoplanet Archive, last updated 2016-05-06. Earth Similarity Index: PHL @ UPR Arecibo.
Frequently Asked Questions About Kepler-561 c
Is Kepler-561 c habitable?
Kepler-561 c is not known to orbit within the habitable zone of Kepler-561, and as a mini-Neptune it is an unlikely candidate for life as we know it.
How far away is Kepler-561 c?
Kepler-561 c is about 2,027 light-years from Earth in the constellation Cygnus. A spacecraft traveling as fast as Voyager 1 (about 17 km/s) would need roughly 35,669,920 years to get there.
How big is Kepler-561 c compared to Earth?
Kepler-561 c has 2.68 times the radius of Earth.
How long is a year on Kepler-561 c?
One orbit around Kepler-561 takes 5.4 Earth days — short enough that 68 of its years would fit into one Earth year.
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