Kepler-691 b
Kepler-691 b is a mini-Neptune orbiting Kepler-691 in the constellation Lyra. It lies about 910 light-years from Earth and was discovered in 2016 using the transit method.
How Big Is Kepler-691 b?
Kepler-691 b has a radius of 2.09 times that of Earth.
Is Kepler-691 b in the Habitable Zone?
The position of Kepler-691 b relative to the habitable zone of Kepler-691 cannot be precisely determined from the available orbital data.
Habitable zone of Kepler-691: 0.169–0.433 AU (conservative: 0.213–0.410 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-691 b — one full orbit around Kepler-691 — lasts 8.11 Earth days, shorter than Mercury's 88-day year.
How Was Kepler-691 b Discovered?
Kepler-691 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-691 b?
Kepler-691 b is 910.4 light-years (279.1 parsecs) from Earth. Light arriving here tonight left the planet around the year 1116. A probe traveling at the speed of Voyager 1 — about 17 km/s, the fastest outbound spacecraft ever launched — would need roughly 16,023,040 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-691 b scores 0.35, ranking #743 of 5,568 planets with a known ESI. For reference, Mars scores about 0.70.
The Host Star: Kepler-691
Kepler-691
- Surface temperature
- 3,715 K (Sun: 5,772 K)
- Mass
- 0.53 M☉
- Radius
- 0.50 R☉
- Age
- 4.0 billion years (Sun: 4.6)
Planetary System
Kepler-691 b is the only planet known to orbit Kepler-691 so far.
Kepler-691 b — Complete Data
| Radius | 2.090 Earth radii (0.186 Jupiter radii) |
|---|---|
| Orbital period | 8.11 days |
| Earth Similarity Index | 0.35 |
| Distance from Earth | 910.4 light-years (279.1 parsecs) |
| Constellation | Lyra |
| 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-691 b
Is Kepler-691 b habitable?
Kepler-691 b is not known to orbit within the habitable zone of Kepler-691, and as a mini-Neptune it is an unlikely candidate for life as we know it.
How far away is Kepler-691 b?
Kepler-691 b is about 910 light-years from Earth in the constellation Lyra. A spacecraft traveling as fast as Voyager 1 (about 17 km/s) would need roughly 16,023,040 years to get there.
How big is Kepler-691 b compared to Earth?
Kepler-691 b has 2.09 times the radius of Earth.
How long is a year on Kepler-691 b?
One orbit around Kepler-691 takes 8.1 Earth days — short enough that 45 of its years would fit into one Earth year.
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