K2-308 b
K2-308 b is a hot Jupiter orbiting K2-308 in the constellation Taurus. It lies about 4,287 light-years from Earth and was discovered in 2019 using the transit method.
How Big Is K2-308 b?
K2-308 b has a radius of 9.92 times that of Earth, or 0.88 times the radius of Jupiter.
Is K2-308 b in the Habitable Zone?
The position of K2-308 b relative to the habitable zone of K2-308 cannot be precisely determined from the available orbital data.
Habitable zone of K2-308: 1.017–2.378 AU (conservative: 1.288–2.254 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 K2-308 b — one full orbit around K2-308 — lasts 3.39 Earth days, shorter than Mercury's 88-day year.
How Was K2-308 b Discovered?
K2-308 b was discovered in 2019 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 K2-308 b?
K2-308 b is 4,287.4 light-years (1,314.5 parsecs) from Earth. Light arriving here tonight left the planet about 4,287 years ago. A probe traveling at the speed of Voyager 1 — about 17 km/s, the fastest outbound spacecraft ever launched — would need roughly 75,458,240 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. K2-308 b scores 0.09, ranking #4,533 of 5,568 planets with a known ESI. For reference, Mars scores about 0.70.
The Host Star: K2-308
K2-308
- Surface temperature
- 6,100 K (Sun: 5,772 K)
- Mass
- 1.09 M☉
- Radius
- 1.24 R☉
Planetary System
K2-308 b is the only planet known to orbit K2-308 so far.
K2-308 b — Complete Data
| Radius | 9.916 Earth radii (0.884 Jupiter radii) |
|---|---|
| Orbital period | 3.39 days |
| Earth Similarity Index | 0.09 |
| Distance from Earth | 4,287.4 light-years (1,314.5 parsecs) |
| Constellation | Taurus |
| Discovery method | Transit |
| Discovery facility | K2 |
| Discovery year | 2019 |
Data: NASA Exoplanet Archive, last updated 2019-06-07. Earth Similarity Index: PHL @ UPR Arecibo.
Frequently Asked Questions About K2-308 b
Is K2-308 b habitable?
K2-308 b is not known to orbit within the habitable zone of K2-308, and as a hot Jupiter it is an unlikely candidate for life as we know it.
How far away is K2-308 b?
K2-308 b is about 4,287 light-years from Earth in the constellation Taurus. A spacecraft traveling as fast as Voyager 1 (about 17 km/s) would need roughly 75,458,240 years to get there.
How big is K2-308 b compared to Earth?
K2-308 b has 9.92 times the radius of Earth.
How long is a year on K2-308 b?
One orbit around K2-308 takes 3.4 Earth days — short enough that 108 of its years would fit into one Earth year.
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