WASP-78 b
WASP-78 b is a hot Jupiter orbiting WASP-78 in the constellation Eridanus. It lies about 2,460 light-years from Earth and was discovered in 2012 using the transit method.
How Big Is WASP-78 b?
WASP-78 b has a radius of 21.63 times that of Earth, or 1.93 times the radius of Jupiter. Its mass is 353 times that of Earth.
Is WASP-78 b in the Habitable Zone?
The position of WASP-78 b relative to the habitable zone of WASP-78 cannot be precisely determined from the available orbital data.
Habitable zone of WASP-78: 2.018–4.717 AU (conservative: 2.556–4.473 AU), per Kopparapu et al. (2014). Earth orbits the Sun at 1 AU.
See the full interactive habitable-zone view in the Exoplanet Explorer app ›
Orbit and Year Length
A year on WASP-78 b — one full orbit around WASP-78 — lasts 2.18 Earth days, shorter than Mercury's 88-day year.
How Was WASP-78 b Discovered?
WASP-78 b was discovered in 2012 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-78 b?
WASP-78 b is 2,460.1 light-years (754.3 parsecs) from Earth. Light arriving here tonight left the planet about 2,460 years ago. A probe traveling at the speed of Voyager 1 — about 17 km/s, the fastest outbound spacecraft ever launched — would need roughly 43,297,760 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-78 b scores 0.04, ranking #5,314 of 5,568 planets with a known ESI. For reference, Mars scores about 0.70.
The Host Star: WASP-78
WASP-78
- Surface temperature
- 6,100 K (Sun: 5,772 K)
- Mass
- 1.87 M☉
- Radius
- 2.46 R☉
Planetary System
WASP-78 b is the only planet known to orbit WASP-78 so far.
WASP-78 b — Complete Data
| Radius | 21.633 Earth radii (1.930 Jupiter radii) |
|---|---|
| Mass | 352.79 Earth masses (1.110 Jupiter masses) |
| Orbital period | 2.18 days |
| Earth Similarity Index | 0.04 |
| Distance from Earth | 2,460.1 light-years (754.3 parsecs) |
| Constellation | Eridanus |
| Discovery method | Transit |
| Discovery facility | SuperWASP |
| Discovery year | 2012 |
Data: NASA Exoplanet Archive, last updated 2018-04-25. Earth Similarity Index: PHL @ UPR Arecibo.
Frequently Asked Questions About WASP-78 b
Is WASP-78 b habitable?
WASP-78 b is not known to orbit within the habitable zone of WASP-78, and as a hot Jupiter it is an unlikely candidate for life as we know it.
How far away is WASP-78 b?
WASP-78 b is about 2,460 light-years from Earth in the constellation Eridanus. A spacecraft traveling as fast as Voyager 1 (about 17 km/s) would need roughly 43,297,760 years to get there.
How big is WASP-78 b compared to Earth?
WASP-78 b has 21.63 times the radius of Earth and about 353 times its mass.
How long is a year on WASP-78 b?
One orbit around WASP-78 takes 2.2 Earth days — short enough that 168 of its years would fit into one Earth year.
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