WASP-20 b
WASP-20 b is a hot Jupiter orbiting WASP-20 in the constellation Cetus. It lies about 691 light-years from Earth and was discovered in 2015 using the transit method.
How Big Is WASP-20 b?
WASP-20 b has a radius of 15.47 times that of Earth, or 1.38 times the radius of Jupiter.
Is WASP-20 b in the Habitable Zone?
The position of WASP-20 b relative to the habitable zone of WASP-20 cannot be precisely determined from the available orbital data.
Temperature on WASP-20 b
The equilibrium temperature of WASP-20 b is about 1,362 K (1,089 °C) — hot enough to melt many metals. This estimate ignores any atmosphere, which could change surface temperatures dramatically — Earth's greenhouse effect adds about 33 °C.
How Was WASP-20 b Discovered?
WASP-20 b was discovered in 2015 using the transit method, with observations from SuperWASP.
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 WASP-20 b?
WASP-20 b is 691.0 light-years (211.9 parsecs) from Earth. Light arriving here tonight left the planet around the year 1335. A probe traveling at the speed of Voyager 1 — about 17 km/s, the fastest outbound spacecraft ever launched — would need roughly 12,161,600 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. WASP-20 b scores 0.06, ranking #5,197 of 5,568 planets with a known ESI. For reference, Mars scores about 0.70.
The Host Star: WASP-20
WASP-20 b belongs to a system of 2 stars; it orbits WASP-20.
WASP-20
- Radius
- 1.24 R☉
Planetary System
WASP-20 b is the only planet known to orbit WASP-20 so far.
WASP-20 b — Complete Data
| Radius | 15.468 Earth radii (1.380 Jupiter radii) |
|---|---|
| Density | 0.16 g/cm³ (Earth: 5.51) |
| Equilibrium temperature | 1,362 K (1,089 °C) |
| Earth Similarity Index | 0.06 |
| Distance from Earth | 691.0 light-years (211.9 parsecs) |
| Constellation | Cetus |
| Discovery method | Transit |
| Discovery facility | SuperWASP |
| Discovery year | 2015 |
Data: NASA Exoplanet Archive, last updated 2025-12-18. Earth Similarity Index: PHL @ UPR Arecibo.
Frequently Asked Questions About WASP-20 b
Is WASP-20 b habitable?
WASP-20 b is not known to orbit within the habitable zone of WASP-20, and as a hot Jupiter it is an unlikely candidate for life as we know it.
How far away is WASP-20 b?
WASP-20 b is about 691 light-years from Earth in the constellation Cetus. A spacecraft traveling as fast as Voyager 1 (about 17 km/s) would need roughly 12,161,600 years to get there.
How big is WASP-20 b compared to Earth?
WASP-20 b has 15.47 times the radius of Earth.
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