WASP-133 b
WASP-133 b is a hot Jupiter orbiting the G4 star WASP-133 in the constellation Microscopium. It lies about 1,824 light-years from Earth and was discovered in 2016 using the transit method.
How Big Is WASP-133 b?
WASP-133 b has a radius of 13.56 times that of Earth, or 1.21 times the radius of Jupiter. Its mass is 369 times that of Earth, giving it a density of 0.88 g/cm³ — closer to gas planets like Jupiter (1.33 g/cm³).
Is WASP-133 b in the Habitable Zone?
WASP-133 b orbits inside the inner edge of the habitable zone of WASP-133. So close to its star, surface conditions are far too hot for liquid water.
Habitable zone of WASP-133: 1.057–2.495 AU (conservative: 1.338–2.365 AU), per Kopparapu et al. (2014). Earth orbits the Sun at 1 AU.
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Temperature on WASP-133 b
The equilibrium temperature of WASP-133 b is about 1,790 K (1,517 °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.
Orbit and Year Length
A year on WASP-133 b — one full orbit around WASP-133 — lasts 2.18 Earth days, shorter than Mercury's 88-day year. It orbits at an average distance of 0.035 AU — closer to its star than Mercury is to the Sun. Its orbit is mildly elliptical (eccentricity 0.17).
How Was WASP-133 b Discovered?
WASP-133 b was discovered in 2016 using the transit method, with observations from SuperWASP-South.
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-133 b?
WASP-133 b is 1,823.5 light-years (559.1 parsecs) from Earth. Light arriving here tonight left the planet about 1,824 years ago. A probe traveling at the speed of Voyager 1 — about 17 km/s, the fastest outbound spacecraft ever launched — would need roughly 32,093,600 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-133 b scores 0.07, ranking #5,010 of 5,568 planets with a known ESI. For reference, Mars scores about 0.70.
The Host Star: WASP-133
WASP-133
- Spectral type
- G4
- Surface temperature
- 5,700 K (Sun: 5,772 K)
- Mass
- 1.16 M☉
- Radius
- 1.44 R☉
- Age
- 6.8 billion years (Sun: 4.6)
Planetary System
WASP-133 b is the only planet known to orbit WASP-133 so far.
WASP-133 b — Complete Data
| Radius | 13.563 Earth radii (1.210 Jupiter radii) |
|---|---|
| Mass | 368.68 Earth masses (1.160 Jupiter masses) |
| Density | 0.88 g/cm³ (Earth: 5.51) |
| Orbital period | 2.18 days |
| Orbital distance | 0.035 AU |
| Eccentricity | 0.170 |
| Equilibrium temperature | 1,790 K (1,517 °C) |
| Earth Similarity Index | 0.07 |
| Distance from Earth | 1,823.5 light-years (559.1 parsecs) |
| Constellation | Microscopium |
| Discovery method | Transit |
| Discovery facility | SuperWASP-South |
| Discovery year | 2016 |
Data: NASA Exoplanet Archive, last updated 2016-05-03. Earth Similarity Index: PHL @ UPR Arecibo.
Frequently Asked Questions About WASP-133 b
Is WASP-133 b habitable?
No — WASP-133 b orbits too close to its star and is too hot for liquid water to exist on its surface.
How far away is WASP-133 b?
WASP-133 b is about 1,824 light-years from Earth in the constellation Microscopium. A spacecraft traveling as fast as Voyager 1 (about 17 km/s) would need roughly 32,093,600 years to get there.
How big is WASP-133 b compared to Earth?
WASP-133 b has 13.56 times the radius of Earth and about 369 times its mass.
How long is a year on WASP-133 b?
One orbit around WASP-133 takes 2.2 Earth days — short enough that 168 of its years would fit into one Earth year.
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