WASP-84 b
WASP-84 b is a hot Jupiter orbiting the K0 star WASP-84 in the constellation Hydra. It lies about 328 light-years from Earth and was discovered in 2014 using the transit method.
How Big Is WASP-84 b?
WASP-84 b has a radius of 10.72 times that of Earth, or 0.96 times the radius of Jupiter. Its mass is 220 times that of Earth, giving it a density of 0.98 g/cm³ — closer to gas planets like Jupiter (1.33 g/cm³).
Is WASP-84 b in the Habitable Zone?
The position of WASP-84 b relative to the habitable zone of WASP-84 cannot be precisely determined from the available orbital data.
Temperature on WASP-84 b
The equilibrium temperature of WASP-84 b is about 732 K (459 °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-84 b — one full orbit around WASP-84 — lasts 8.52 Earth days, shorter than Mercury's 88-day year. It orbits at an average distance of 0.078 AU — closer to its star than Mercury is to the Sun.
How Was WASP-84 b Discovered?
WASP-84 b was discovered in 2014 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-84 b?
WASP-84 b is 328.1 light-years (100.6 parsecs) from Earth. Light arriving here tonight left the planet around the year 1698. A probe traveling at the speed of Voyager 1 — about 17 km/s, the fastest outbound spacecraft ever launched — would need roughly 5,774,560 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-84 b scores 0.09, ranking #4,481 of 5,568 planets with a known ESI. For reference, Mars scores about 0.70.
The Host Star: WASP-84
WASP-84
- Spectral type
- K0
- Mass
- 0.85 M☉
- Radius
- 0.77 R☉
The WASP-84 Planetary System
WASP-84 b is one of 2 known planets in the WASP-84 system. Its siblings:
- WASP-84 c (Super Earth)
WASP-84 b — Complete Data
| Radius | 10.720 Earth radii (0.956 Jupiter radii) |
|---|---|
| Mass | 220.00 Earth masses (0.692 Jupiter masses) |
| Density | 0.98 g/cm³ (Earth: 5.51) |
| Orbital period | 8.52 days |
| Orbital distance | 0.078 AU |
| Equilibrium temperature | 732 K (459 °C) |
| Earth Similarity Index | 0.09 |
| Distance from Earth | 328.1 light-years (100.6 parsecs) |
| Constellation | Hydra |
| Discovery method | Transit |
| Discovery facility | SuperWASP |
| Discovery year | 2014 |
Data: NASA Exoplanet Archive, last updated 2023-07-10. Earth Similarity Index: PHL @ UPR Arecibo.
Frequently Asked Questions About WASP-84 b
Is WASP-84 b habitable?
WASP-84 b is not known to orbit within the habitable zone of WASP-84, and as a hot Jupiter it is an unlikely candidate for life as we know it.
How far away is WASP-84 b?
WASP-84 b is about 328 light-years from Earth in the constellation Hydra. A spacecraft traveling as fast as Voyager 1 (about 17 km/s) would need roughly 5,774,560 years to get there.
How big is WASP-84 b compared to Earth?
WASP-84 b has 10.72 times the radius of Earth and about 220 times its mass.
How long is a year on WASP-84 b?
One orbit around WASP-84 takes 8.5 Earth days — short enough that 43 of its years would fit into one Earth year.
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