WASP-156 b
WASP-156 b is a hot Jupiter orbiting the K3 V star WASP-156 in the constellation Cetus. It lies about 398 light-years from Earth and was discovered in 2017 using the transit method.
How Big Is WASP-156 b?
WASP-156 b has a radius of 6.15 times that of Earth, or 0.55 times the radius of Jupiter. Its mass is 42.0 times that of Earth, giving it a density of 0.99 g/cm³ — closer to gas planets like Jupiter (1.33 g/cm³).
Is WASP-156 b in the Habitable Zone?
The position of WASP-156 b relative to the habitable zone of WASP-156 cannot be precisely determined from the available orbital data.
Orbit and Year Length
A year on WASP-156 b — one full orbit around WASP-156 — lasts 3.84 Earth days, shorter than Mercury's 88-day year. It orbits at an average distance of 0.046 AU — closer to its star than Mercury is to the Sun. Its orbit is mildly elliptical (eccentricity 0.16).
How Was WASP-156 b Discovered?
WASP-156 b was discovered in 2017 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-156 b?
WASP-156 b is 398.1 light-years (122.1 parsecs) from Earth. Light arriving here tonight left the planet around the year 1628. A probe traveling at the speed of Voyager 1 — about 17 km/s, the fastest outbound spacecraft ever launched — would need roughly 7,006,560 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-156 b scores 0.14, ranking #4,243 of 5,566 planets with a known ESI. For reference, Mars scores about 0.70.
The Host Star: WASP-156
WASP-156
- Spectral type
- K3 V
- Surface temperature
- 5,036 K (Sun: 5,772 K)
Planetary System
WASP-156 b is the only planet known to orbit WASP-156 so far.
WASP-156 b — Complete Data
| Radius | 6.150 Earth radii (0.549 Jupiter radii) |
|---|---|
| Mass | 42.00 Earth masses (0.132 Jupiter masses) |
| Density | 0.99 g/cm³ (Earth: 5.51) |
| Orbital period | 3.84 days |
| Orbital distance | 0.046 AU |
| Eccentricity | 0.160 |
| Earth Similarity Index | 0.14 |
| Distance from Earth | 398.1 light-years (122.1 parsecs) |
| Constellation | Cetus |
| Discovery method | Transit |
| Discovery facility | SuperWASP |
| Discovery year | 2017 |
Data: NASA Exoplanet Archive, last updated 2026-07-30. Earth Similarity Index: PHL @ UPR Arecibo.
Frequently Asked Questions About WASP-156 b
Is WASP-156 b habitable?
WASP-156 b is not known to orbit within the habitable zone of WASP-156, and as a hot Jupiter it is an unlikely candidate for life as we know it.
How far away is WASP-156 b?
WASP-156 b is about 398 light-years from Earth in the constellation Cetus. A spacecraft traveling as fast as Voyager 1 (about 17 km/s) would need roughly 7,006,560 years to get there.
How big is WASP-156 b compared to Earth?
WASP-156 b has 6.15 times the radius of Earth and about 42.0 times its mass.
How long is a year on WASP-156 b?
One orbit around WASP-156 takes 3.8 Earth days — short enough that 95 of its years would fit into one Earth year.
Explore WASP-156 b in the app
Browse, filter and compare 6,000+ exoplanets on iPhone, iPad and Apple Watch — with habitable-zone views, widgets and offline data.
