KOI-217 b
KOI-217 b is a hot Jupiter orbiting KOI-217 in the constellation Cygnus. It lies about 2,983 light-years from Earth and was discovered in 2010 using the transit method.
How Big Is KOI-217 b?
KOI-217 b has a radius of 12.44 times that of Earth, or 1.11 times the radius of Jupiter.
Is KOI-217 b in the Habitable Zone?
KOI-217 b orbits inside the inner edge of the habitable zone of KOI-217. So close to its star, surface conditions are far too hot for liquid water.
Habitable zone of KOI-217: 0.603–1.429 AU (conservative: 0.763–1.355 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 KOI-217 b — one full orbit around KOI-217 — lasts 3.91 Earth days, shorter than Mercury's 88-day year. It orbits at an average distance of 0.048 AU — closer to its star than Mercury is to the Sun.
How Was KOI-217 b Discovered?
KOI-217 b was discovered in 2010 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 KOI-217 b?
KOI-217 b is 2,983.3 light-years (914.7 parsecs) from Earth. Light arriving here tonight left the planet about 2,983 years ago. A probe traveling at the speed of Voyager 1 — about 17 km/s, the fastest outbound spacecraft ever launched — would need roughly 52,506,080 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. KOI-217 b scores 0.08, ranking #4,788 of 5,568 planets with a known ESI. For reference, Mars scores about 0.70.
The Host Star: KOI-217
KOI-217
- Surface temperature
- 5,545 K (Sun: 5,772 K)
- Mass
- 0.95 M☉
- Radius
- 0.86 R☉
Planetary System
KOI-217 b is the only planet known to orbit KOI-217 so far.
KOI-217 b — Complete Data
| Radius | 12.442 Earth radii (1.110 Jupiter radii) |
|---|---|
| Orbital period | 3.91 days |
| Orbital distance | 0.048 AU |
| Earth Similarity Index | 0.08 |
| Distance from Earth | 2,983.3 light-years (914.7 parsecs) |
| Constellation | Cygnus |
| Discovery method | Transit |
| Discovery facility | Kepler |
| Discovery year | 2010 |
Data: NASA Exoplanet Archive, last updated 2014-05-14. Earth Similarity Index: PHL @ UPR Arecibo.
Frequently Asked Questions About KOI-217 b
Is KOI-217 b habitable?
No — KOI-217 b orbits too close to its star and is too hot for liquid water to exist on its surface.
How far away is KOI-217 b?
KOI-217 b is about 2,983 light-years from Earth in the constellation Cygnus. A spacecraft traveling as fast as Voyager 1 (about 17 km/s) would need roughly 52,506,080 years to get there.
How big is KOI-217 b compared to Earth?
KOI-217 b has 12.44 times the radius of Earth.
How long is a year on KOI-217 b?
One orbit around KOI-217 takes 3.9 Earth days — short enough that 94 of its years would fit into one Earth year.
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