WASP-7 b
WASP-7 b is a hot Jupiter orbiting WASP-7 in the constellation Microscopium. It lies about 529 light-years from Earth and was discovered in 2008 using the transit method.
How Big Is WASP-7 b?
WASP-7 b has a radius of 14.91 times that of Earth, or 1.33 times the radius of Jupiter. Its mass is 305 times that of Earth, giving it a density of 0.55 g/cm³ — closer to gas planets like Jupiter (1.33 g/cm³).
Is WASP-7 b in the Habitable Zone?
WASP-7 b orbits inside the inner edge of the habitable zone of WASP-7. So close to its star, surface conditions are far too hot for liquid water.
Habitable zone of WASP-7: 1.270–2.952 AU (conservative: 1.608–2.799 AU), per Kopparapu et al. (2014). Earth orbits the Sun at 1 AU.
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Temperature on WASP-7 b
The equilibrium temperature of WASP-7 b is about 1,487 K (1,214 °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-7 b — one full orbit around WASP-7 — lasts 4.95 Earth days, shorter than Mercury's 88-day year. It orbits at an average distance of 0.062 AU — closer to its star than Mercury is to the Sun.
How Was WASP-7 b Discovered?
WASP-7 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-7 b?
WASP-7 b is 529.4 light-years (162.3 parsecs) from Earth. Light arriving here tonight left the planet around the year 1497. A probe traveling at the speed of Voyager 1 — about 17 km/s, the fastest outbound spacecraft ever launched — would need roughly 9,317,440 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-7 b scores 0.06, ranking #5,121 of 5,568 planets with a known ESI. For reference, Mars scores about 0.70.
The Host Star: WASP-7
WASP-7
- Surface temperature
- 6,400 K (Sun: 5,772 K)
- Mass
- 1.28 M☉
- Radius
- 1.43 R☉
- Age
- 2.4 billion years (Sun: 4.6)
Planetary System
WASP-7 b is the only planet known to orbit WASP-7 so far.
WASP-7 b — Complete Data
| Radius | 14.908 Earth radii (1.330 Jupiter radii) |
|---|---|
| Mass | 305.12 Earth masses (0.960 Jupiter masses) |
| Density | 0.55 g/cm³ (Earth: 5.51) |
| Orbital period | 4.95 days |
| Orbital distance | 0.062 AU |
| Equilibrium temperature | 1,487 K (1,214 °C) |
| Earth Similarity Index | 0.06 |
| Distance from Earth | 529.4 light-years (162.3 parsecs) |
| Constellation | Microscopium |
| Discovery method | Transit |
| Discovery facility | SuperWASP |
| Discovery year | 2008 |
Data: NASA Exoplanet Archive, last updated 2018-05-14. Earth Similarity Index: PHL @ UPR Arecibo.
Frequently Asked Questions About WASP-7 b
Is WASP-7 b habitable?
No — WASP-7 b orbits too close to its star and is too hot for liquid water to exist on its surface.
How far away is WASP-7 b?
WASP-7 b is about 529 light-years from Earth in the constellation Microscopium. A spacecraft traveling as fast as Voyager 1 (about 17 km/s) would need roughly 9,317,440 years to get there.
How big is WASP-7 b compared to Earth?
WASP-7 b has 14.91 times the radius of Earth and about 305 times its mass.
How long is a year on WASP-7 b?
One orbit around WASP-7 takes 5.0 Earth days — short enough that 74 of its years would fit into one Earth year.
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