Kepler-1731 b
Kepler-1731 b is a mini-Neptune orbiting Kepler-1731 in the constellation Lyra. It lies about 554 light-years from Earth and was discovered in 2021 using the transit method.
How Big Is Kepler-1731 b?
Kepler-1731 b has a radius of 2.93 times that of Earth.
Is Kepler-1731 b in the Habitable Zone?
The position of Kepler-1731 b relative to the habitable zone of Kepler-1731 cannot be precisely determined from the available orbital data.
Habitable zone of Kepler-1731: 0.401–0.976 AU (conservative: 0.508–0.925 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-1731 b — one full orbit around Kepler-1731 — lasts 21.8 Earth days, shorter than Mercury's 88-day year.
How Was Kepler-1731 b Discovered?
Kepler-1731 b was discovered in 2021 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-1731 b?
Kepler-1731 b is 554.3 light-years (169.9 parsecs) from Earth. Light arriving here tonight left the planet around the year 1472. A probe traveling at the speed of Voyager 1 — about 17 km/s, the fastest outbound spacecraft ever launched — would need roughly 9,755,680 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-1731 b scores 0.30, ranking #1,295 of 5,568 planets with a known ESI. For reference, Mars scores about 0.70.
The Host Star: Kepler-1731
Kepler-1731
- Surface temperature
- 4,859 K (Sun: 5,772 K)
- Mass
- 0.78 M☉
- Radius
- 0.72 R☉
Planetary System
Kepler-1731 b is the only planet known to orbit Kepler-1731 so far.
Kepler-1731 b — Complete Data
| Radius | 2.933 Earth radii (0.262 Jupiter radii) |
|---|---|
| Orbital period | 21.76 days |
| Earth Similarity Index | 0.30 |
| Distance from Earth | 554.3 light-years (169.9 parsecs) |
| Constellation | Lyra |
| Discovery method | Transit |
| Discovery facility | Kepler |
| Discovery year | 2021 |
Data: NASA Exoplanet Archive, last updated 2021-12-05. Earth Similarity Index: PHL @ UPR Arecibo.
Frequently Asked Questions About Kepler-1731 b
Is Kepler-1731 b habitable?
Kepler-1731 b is not known to orbit within the habitable zone of Kepler-1731, and as a mini-Neptune it is an unlikely candidate for life as we know it.
How far away is Kepler-1731 b?
Kepler-1731 b is about 554 light-years from Earth in the constellation Lyra. A spacecraft traveling as fast as Voyager 1 (about 17 km/s) would need roughly 9,755,680 years to get there.
How big is Kepler-1731 b compared to Earth?
Kepler-1731 b has 2.93 times the radius of Earth.
How long is a year on Kepler-1731 b?
One orbit around Kepler-1731 takes 21.8 Earth days — short enough that 17 of its years would fit into one Earth year.
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