Kepler-61 b
Kepler-61 b is a mini-Neptune orbiting the K7 V star Kepler-61 in the constellation Cygnus. It lies about 1,093 light-years from Earth and was discovered in 2013 using the transit method.
How Big Is Kepler-61 b?
Kepler-61 b has a radius of 2.15 times that of Earth.
Is Kepler-61 b in the Habitable Zone?
The position of Kepler-61 b relative to the habitable zone of Kepler-61 cannot be precisely determined from the available orbital data.
Habitable zone of Kepler-61: 0.243–0.614 AU (conservative: 0.308–0.583 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 ›
Temperature on Kepler-61 b
The equilibrium temperature of Kepler-61 b is about 273 K (-0 °C) — in a range broadly comparable to Earth, whose equilibrium temperature is 255 K. This estimate ignores any atmosphere, which could change surface temperatures dramatically — Earth's greenhouse effect adds about 33 °C.
Orbit and Year Length
A year on Kepler-61 b — one full orbit around Kepler-61 — lasts 59.9 Earth days, shorter than Mercury's 88-day year. Its orbit is mildly elliptical (eccentricity 0.25).
How Was Kepler-61 b Discovered?
Kepler-61 b was discovered in 2013 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-61 b?
Kepler-61 b is 1,092.9 light-years (335.1 parsecs) from Earth. Light arriving here tonight left the planet about 1,093 years ago. A probe traveling at the speed of Voyager 1 — about 17 km/s, the fastest outbound spacecraft ever launched — would need roughly 19,235,040 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-61 b scores 0.67, ranking #78 of 5,568 planets with a known ESI. For reference, Mars scores about 0.70.
The Host Star: Kepler-61
Kepler-61
- Spectral type
- K7 V
- Surface temperature
- 4,017 K (Sun: 5,772 K)
- Mass
- 0.64 M☉
- Radius
- 0.62 R☉
- Age
- 1.0 billion years (Sun: 4.6)
Planetary System
Kepler-61 b is the only planet known to orbit Kepler-61 so far.
Kepler-61 b — Complete Data
| Radius | 2.150 Earth radii (0.192 Jupiter radii) |
|---|---|
| Orbital period | 59.88 days |
| Eccentricity | 0.250 |
| Equilibrium temperature | 273 K (-0 °C) |
| Earth Similarity Index | 0.67 |
| Distance from Earth | 1,092.9 light-years (335.1 parsecs) |
| Constellation | Cygnus |
| Discovery method | Transit |
| Discovery facility | Kepler |
| Discovery year | 2013 |
Data: NASA Exoplanet Archive, last updated 2014-05-14. Earth Similarity Index: PHL @ UPR Arecibo.
Frequently Asked Questions About Kepler-61 b
Is Kepler-61 b habitable?
Kepler-61 b is not known to orbit within the habitable zone of Kepler-61, and as a mini-Neptune it is an unlikely candidate for life as we know it.
How far away is Kepler-61 b?
Kepler-61 b is about 1,093 light-years from Earth in the constellation Cygnus. A spacecraft traveling as fast as Voyager 1 (about 17 km/s) would need roughly 19,235,040 years to get there.
How big is Kepler-61 b compared to Earth?
Kepler-61 b has 2.15 times the radius of Earth.
How long is a year on Kepler-61 b?
One orbit around Kepler-61 takes 59.9 Earth days.
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