Kepler-581 b
Kepler-581 b is a mini-Neptune orbiting Kepler-581 in the constellation Cygnus. It lies about 2,295 light-years from Earth and was discovered in 2016 using the transit method.
How Big Is Kepler-581 b?
Kepler-581 b has a radius of 2.63 times that of Earth.
Is Kepler-581 b in the Habitable Zone?
The position of Kepler-581 b relative to the habitable zone of Kepler-581 cannot be precisely determined from the available orbital data.
Habitable zone of Kepler-581: 0.749–1.765 AU (conservative: 0.949–1.674 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-581 b — one full orbit around Kepler-581 — lasts 40.6 Earth days, shorter than Mercury's 88-day year.
How Was Kepler-581 b Discovered?
Kepler-581 b 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-581 b?
Kepler-581 b is 2,295.3 light-years (703.8 parsecs) from Earth. Light arriving here tonight left the planet about 2,295 years ago. A probe traveling at the speed of Voyager 1 — about 17 km/s, the fastest outbound spacecraft ever launched — would need roughly 40,397,280 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-581 b scores 0.31, ranking #1,100 of 5,568 planets with a known ESI. For reference, Mars scores about 0.70.
The Host Star: Kepler-581
Kepler-581
- Surface temperature
- 5,772 K (Sun: 5,772 K)
- Mass
- 1.00 M☉
- Radius
- 1.00 R☉
- Age
- 4.1 billion years (Sun: 4.6)
Planetary System
Kepler-581 b is the only planet known to orbit Kepler-581 so far.
Kepler-581 b — Complete Data
| Radius | 2.630 Earth radii (0.235 Jupiter radii) |
|---|---|
| Orbital period | 40.61 days |
| Earth Similarity Index | 0.31 |
| Distance from Earth | 2,295.3 light-years (703.8 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-581 b
Is Kepler-581 b habitable?
Kepler-581 b is not known to orbit within the habitable zone of Kepler-581, and as a mini-Neptune it is an unlikely candidate for life as we know it.
How far away is Kepler-581 b?
Kepler-581 b is about 2,295 light-years from Earth in the constellation Cygnus. A spacecraft traveling as fast as Voyager 1 (about 17 km/s) would need roughly 40,397,280 years to get there.
How big is Kepler-581 b compared to Earth?
Kepler-581 b has 2.63 times the radius of Earth.
How long is a year on Kepler-581 b?
One orbit around Kepler-581 takes 40.6 Earth days.
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