WASP-178 b
WASP-178 b is a hot Jupiter orbiting the A1 IV-V star WASP-178 in the constellation Lupus. It lies about 1,395 light-years from Earth and was discovered in 2019 using the transit method.
How Big Is WASP-178 b?
WASP-178 b has a radius of 20.29 times that of Earth, or 1.81 times the radius of Jupiter. Its mass is 528 times that of Earth, giving it a density of 0.37 g/cm³ — closer to gas planets like Jupiter (1.33 g/cm³).
Is WASP-178 b in the Habitable Zone?
The position of WASP-178 b relative to the habitable zone of WASP-178 cannot be precisely determined from the available orbital data.
Temperature on WASP-178 b
The equilibrium temperature of WASP-178 b is about 2,470 K (2,197 °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-178 b — one full orbit around WASP-178 — lasts 3.34 Earth days, shorter than Mercury's 88-day year. It orbits at an average distance of 0.056 AU — closer to its star than Mercury is to the Sun.
How Was WASP-178 b Discovered?
WASP-178 b was discovered in 2019 using the transit method, with observations from WASP-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-178 b?
WASP-178 b is 1,394.9 light-years (427.7 parsecs) from Earth. Light arriving here tonight left the planet about 1,395 years ago. A probe traveling at the speed of Voyager 1 — about 17 km/s, the fastest outbound spacecraft ever launched — would need roughly 24,550,240 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-178 b scores 0.05, ranking #5,304 of 5,568 planets with a known ESI. For reference, Mars scores about 0.70.
The Host Star: WASP-178
WASP-178
- Spectral type
- A1 IV-V
- Surface temperature
- 9,360 K (Sun: 5,772 K)
- Mass
- 2.07 M☉
- Radius
- 1.67 R☉
Planetary System
WASP-178 b is the only planet known to orbit WASP-178 so far.
WASP-178 b — Complete Data
| Radius | 20.288 Earth radii (1.810 Jupiter radii) |
|---|---|
| Mass | 527.60 Earth masses (1.660 Jupiter masses) |
| Density | 0.37 g/cm³ (Earth: 5.51) |
| Orbital period | 3.34 days |
| Orbital distance | 0.056 AU |
| Equilibrium temperature | 2,470 K (2,197 °C) |
| Earth Similarity Index | 0.05 |
| Distance from Earth | 1,394.9 light-years (427.7 parsecs) |
| Constellation | Lupus |
| Discovery method | Transit |
| Discovery facility | WASP-South |
| Discovery year | 2019 |
Data: NASA Exoplanet Archive, last updated 2019-10-02. Earth Similarity Index: PHL @ UPR Arecibo.
Frequently Asked Questions About WASP-178 b
Is WASP-178 b habitable?
WASP-178 b is not known to orbit within the habitable zone of WASP-178, and as a hot Jupiter it is an unlikely candidate for life as we know it.
How far away is WASP-178 b?
WASP-178 b is about 1,395 light-years from Earth in the constellation Lupus. A spacecraft traveling as fast as Voyager 1 (about 17 km/s) would need roughly 24,550,240 years to get there.
How big is WASP-178 b compared to Earth?
WASP-178 b has 20.29 times the radius of Earth and about 528 times its mass.
How long is a year on WASP-178 b?
One orbit around WASP-178 takes 3.3 Earth days — short enough that 109 of its years would fit into one Earth year.
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