K2-387 b
K2-387 b is a cold gas giant orbiting K2-387 in the constellation Pisces. It lies about 869 light-years from Earth and was discovered in 2022 using the transit method.
How Big Is K2-387 b?
K2-387 b has a radius of 7.32 times that of Earth, or 0.65 times the radius of Jupiter.
Is K2-387 b in the Habitable Zone?
The position of K2-387 b relative to the habitable zone of K2-387 cannot be precisely determined from the available orbital data.
Habitable zone of K2-387: 0.183–0.472 AU (conservative: 0.231–0.448 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 K2-387 b — one full orbit around K2-387 — lasts 28.7 Earth days, shorter than Mercury's 88-day year.
How Was K2-387 b Discovered?
K2-387 b was discovered in 2022 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 K2-387 b?
K2-387 b is 868.6 light-years (266.3 parsecs) from Earth. Light arriving here tonight left the planet around the year 1158. A probe traveling at the speed of Voyager 1 — about 17 km/s, the fastest outbound spacecraft ever launched — would need roughly 15,287,360 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. K2-387 b scores 0.38, ranking #553 of 5,568 planets with a known ESI. For reference, Mars scores about 0.70.
The Host Star: K2-387
K2-387
- Surface temperature
- 3,572 K (Sun: 5,772 K)
- Mass
- 0.57 M☉
- Radius
- 0.59 R☉
Planetary System
K2-387 b is the only planet known to orbit K2-387 so far.
K2-387 b — Complete Data
| Radius | 7.322 Earth radii (0.653 Jupiter radii) |
|---|---|
| Orbital period | 28.74 days |
| Earth Similarity Index | 0.38 |
| Distance from Earth | 868.6 light-years (266.3 parsecs) |
| Constellation | Pisces |
| Discovery method | Transit |
| Discovery facility | K2 |
| Discovery year | 2022 |
Data: NASA Exoplanet Archive, last updated 2022-03-16. Earth Similarity Index: PHL @ UPR Arecibo.
Frequently Asked Questions About K2-387 b
Is K2-387 b habitable?
K2-387 b is not known to orbit within the habitable zone of K2-387, and as a cold gas giant it is an unlikely candidate for life as we know it.
How far away is K2-387 b?
K2-387 b is about 869 light-years from Earth in the constellation Pisces. A spacecraft traveling as fast as Voyager 1 (about 17 km/s) would need roughly 15,287,360 years to get there.
How big is K2-387 b compared to Earth?
K2-387 b has 7.32 times the radius of Earth.
How long is a year on K2-387 b?
One orbit around K2-387 takes 28.7 Earth days — short enough that 13 of its years would fit into one Earth year.
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