WASP-25 b
WASP-25 b is a hot Jupiter orbiting WASP-25 in the constellation Hydra. It lies about 690 light-years from Earth and was discovered in 2010 using the transit method.
How Big Is WASP-25 b?
WASP-25 b has a radius of 13.81 times that of Earth, or 1.23 times the radius of Jupiter. Its mass is 179 times that of Earth, giving it a density of 0.40 g/cm³ — closer to gas planets like Jupiter (1.33 g/cm³).
Is WASP-25 b in the Habitable Zone?
The position of WASP-25 b relative to the habitable zone of WASP-25 cannot be precisely determined from the available orbital data.
Habitable zone of WASP-25: 0.648–1.530 AU (conservative: 0.821–1.451 AU), per Kopparapu et al. (2014). Earth orbits the Sun at 1 AU.
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Temperature on WASP-25 b
The equilibrium temperature of WASP-25 b is about 1,217 K (944 °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. It receives 341 times the stellar energy that Earth gets from the Sun.
Orbit and Year Length
A year on WASP-25 b — one full orbit around WASP-25 — lasts 3.76 Earth days, shorter than Mercury's 88-day year.
How Was WASP-25 b Discovered?
WASP-25 b was discovered in 2010 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-25 b?
WASP-25 b is 689.5 light-years (211.4 parsecs) from Earth. Light arriving here tonight left the planet around the year 1337. A probe traveling at the speed of Voyager 1 — about 17 km/s, the fastest outbound spacecraft ever launched — would need roughly 12,135,200 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-25 b scores 0.08, ranking #4,737 of 5,568 planets with a known ESI. For reference, Mars scores about 0.70.
The Host Star: WASP-25
WASP-25
- Surface temperature
- 5,697 K (Sun: 5,772 K)
- Mass
- 0.96 M☉
- Radius
- 0.88 R☉
- Age
- 1.9 billion years (Sun: 4.6)
Planetary System
WASP-25 b is the only planet known to orbit WASP-25 so far.
WASP-25 b — Complete Data
| Radius | 13.809 Earth radii (1.232 Jupiter radii) |
|---|---|
| Mass | 179.26 Earth masses (0.564 Jupiter masses) |
| Density | 0.40 g/cm³ (Earth: 5.51) |
| Orbital period | 3.76 days |
| Equilibrium temperature | 1,217 K (944 °C) |
| Stellar irradiation | 341.00× Earth |
| Earth Similarity Index | 0.08 |
| Distance from Earth | 689.5 light-years (211.4 parsecs) |
| Constellation | Hydra |
| Discovery method | Transit |
| Discovery facility | SuperWASP |
| Discovery year | 2010 |
Data: NASA Exoplanet Archive, last updated 2025-10-09. Earth Similarity Index: PHL @ UPR Arecibo.
Frequently Asked Questions About WASP-25 b
Is WASP-25 b habitable?
WASP-25 b is not known to orbit within the habitable zone of WASP-25, and as a hot Jupiter it is an unlikely candidate for life as we know it.
How far away is WASP-25 b?
WASP-25 b is about 690 light-years from Earth in the constellation Hydra. A spacecraft traveling as fast as Voyager 1 (about 17 km/s) would need roughly 12,135,200 years to get there.
How big is WASP-25 b compared to Earth?
WASP-25 b has 13.81 times the radius of Earth and about 179 times its mass.
How long is a year on WASP-25 b?
One orbit around WASP-25 takes 3.8 Earth days — short enough that 97 of its years would fit into one Earth year.
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