WASP-12 b
WASP-12 b is a hot Jupiter orbiting WASP-12 in the constellation Auriga. It lies about 1,394 light-years from Earth and was discovered in 2008 using the transit method.
How Big Is WASP-12 b?
WASP-12 b has a radius of 22.03 times that of Earth, or 1.97 times the radius of Jupiter.
Is WASP-12 b in the Habitable Zone?
WASP-12 b orbits inside the inner edge of the habitable zone of WASP-12. So close to its star, surface conditions are far too hot for liquid water.
Habitable zone of WASP-12: 1.448–3.373 AU (conservative: 1.834–3.198 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 WASP-12 b — one full orbit around WASP-12 — lasts just 26.2 hours, shorter than Mercury's 88-day year. It orbits at an average distance of 0.023 AU — closer to its star than Mercury is to the Sun.
How Was WASP-12 b Discovered?
WASP-12 b was discovered in 2008 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-12 b?
WASP-12 b is 1,393.5 light-years (427.2 parsecs) from Earth. Light arriving here tonight left the planet about 1,394 years ago. A probe traveling at the speed of Voyager 1 — about 17 km/s, the fastest outbound spacecraft ever launched — would need roughly 24,525,600 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-12 b scores 0.04, ranking #5,315 of 5,568 planets with a known ESI. For reference, Mars scores about 0.70.
The Host Star: WASP-12
WASP-12 b belongs to a system of 3 stars; it orbits WASP-12.
WASP-12
- Surface temperature
- 6,265 K (Sun: 5,772 K)
- Mass
- 1.33 M☉
- Radius
- 1.69 R☉
- Age
- 3.1 billion years (Sun: 4.6)
Planetary System
WASP-12 b is the only planet known to orbit WASP-12 so far.
WASP-12 b — Complete Data
| Radius | 22.026 Earth radii (1.965 Jupiter radii) |
|---|---|
| Orbital period | 1.09 days |
| Orbital distance | 0.023 AU |
| Earth Similarity Index | 0.04 |
| Distance from Earth | 1,393.5 light-years (427.2 parsecs) |
| Constellation | Auriga |
| Discovery method | Transit |
| Discovery facility | SuperWASP |
| Discovery year | 2008 |
Data: NASA Exoplanet Archive, last updated 2025-02-12. Earth Similarity Index: PHL @ UPR Arecibo.
Frequently Asked Questions About WASP-12 b
Is WASP-12 b habitable?
No — WASP-12 b orbits too close to its star and is too hot for liquid water to exist on its surface.
How far away is WASP-12 b?
WASP-12 b is about 1,394 light-years from Earth in the constellation Auriga. A spacecraft traveling as fast as Voyager 1 (about 17 km/s) would need roughly 24,525,600 years to get there.
How big is WASP-12 b compared to Earth?
WASP-12 b has 22.03 times the radius of Earth.
How long is a year on WASP-12 b?
One orbit around WASP-12 takes 1.1 Earth days — short enough that 335 of its years would fit into one Earth year.
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