K2-210 b
K2-210 b is a terrestrial planet orbiting K2-210 in the constellation Cetus. It lies about 576 light-years from Earth and was discovered in 2018 using the transit method.
How Big Is K2-210 b?
K2-210 b has a radius of 0.86 times that of Earth.
Is K2-210 b in the Habitable Zone?
The position of K2-210 b relative to the habitable zone of K2-210 cannot be precisely determined from the available orbital data.
Habitable zone of K2-210: 0.615–1.461 AU (conservative: 0.779–1.385 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 K2-210 b — one full orbit around K2-210 — lasts just 13.7 hours, shorter than Mercury's 88-day year.
How Was K2-210 b Discovered?
K2-210 b was discovered in 2018 using the transit method, with observations from K2.
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 K2-210 b?
K2-210 b is 575.7 light-years (176.5 parsecs) from Earth. Light arriving here tonight left the planet around the year 1451. A probe traveling at the speed of Voyager 1 — about 17 km/s, the fastest outbound spacecraft ever launched — would need roughly 10,132,320 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. K2-210 b scores 0.29, ranking #1,775 of 5,568 planets with a known ESI. For reference, Mars scores about 0.70.
The Host Star: K2-210
K2-210
- Surface temperature
- 5,500 K (Sun: 5,772 K)
- Radius
- 0.89 R☉
Planetary System
K2-210 b is the only planet known to orbit K2-210 so far.
K2-210 b — Complete Data
| Radius | 0.860 Earth radii (0.077 Jupiter radii) |
|---|---|
| Orbital period | 0.57 days |
| Earth Similarity Index | 0.29 |
| Distance from Earth | 575.7 light-years (176.5 parsecs) |
| Constellation | Cetus |
| Discovery method | Transit |
| Discovery facility | K2 |
| Discovery year | 2018 |
Data: NASA Exoplanet Archive, last updated 2022-03-28. Earth Similarity Index: PHL @ UPR Arecibo.
Frequently Asked Questions About K2-210 b
Is K2-210 b habitable?
K2-210 b is not known to orbit within the habitable zone of K2-210, and as a terrestrial planet it is an unlikely candidate for life as we know it.
How far away is K2-210 b?
K2-210 b is about 576 light-years from Earth in the constellation Cetus. A spacecraft traveling as fast as Voyager 1 (about 17 km/s) would need roughly 10,132,320 years to get there.
How big is K2-210 b compared to Earth?
K2-210 b has 0.86 times the radius of Earth.
How long is a year on K2-210 b?
One orbit around K2-210 takes 0.6 Earth days — short enough that 641 of its years would fit into one Earth year.
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