HATS-5 b
HATS-5 b is a hot Jupiter orbiting the G star HATS-5 in the constellation Eridanus. It lies about 804 light-years from Earth and was discovered in 2014 using the transit method.
How Big Is HATS-5 b?
HATS-5 b has a radius of 10.22 times that of Earth, or 0.91 times the radius of Jupiter. Its mass is 75.3 times that of Earth, giving it a density of 0.39 g/cm³ — closer to gas planets like Jupiter (1.33 g/cm³).
Is HATS-5 b in the Habitable Zone?
HATS-5 b orbits inside the inner edge of the habitable zone of HATS-5. So close to its star, surface conditions are far too hot for liquid water.
Habitable zone of HATS-5: 0.566–1.354 AU (conservative: 0.718–1.284 AU), per Kopparapu et al. (2014). Earth orbits the Sun at 1 AU.
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Temperature on HATS-5 b
The equilibrium temperature of HATS-5 b is about 1,025 K (752 °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 HATS-5 b — one full orbit around HATS-5 — lasts 4.76 Earth days, shorter than Mercury's 88-day year. It orbits at an average distance of 0.054 AU — closer to its star than Mercury is to the Sun. Its orbit is nearly circular (eccentricity 0.019).
How Was HATS-5 b Discovered?
HATS-5 b was discovered in 2014 using the transit method, with observations from HATSouth.
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 HATS-5 b?
HATS-5 b is 803.6 light-years (246.4 parsecs) from Earth. Light arriving here tonight left the planet around the year 1223. A probe traveling at the speed of Voyager 1 — about 17 km/s, the fastest outbound spacecraft ever launched — would need roughly 14,143,360 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. HATS-5 b scores 0.09, ranking #4,512 of 5,568 planets with a known ESI. For reference, Mars scores about 0.70.
The Host Star: HATS-5
HATS-5
- Spectral type
- G
- Surface temperature
- 5,304 K (Sun: 5,772 K)
- Mass
- 0.94 M☉
- Radius
- 0.87 R☉
- Luminosity
- 0.5395 L☉
- Age
- 3.6 billion years (Sun: 4.6)
Planetary System
HATS-5 b is the only planet known to orbit HATS-5 so far.
HATS-5 b — Complete Data
| Radius | 10.223 Earth radii (0.912 Jupiter radii) |
|---|---|
| Mass | 75.32 Earth masses (0.237 Jupiter masses) |
| Density | 0.39 g/cm³ (Earth: 5.51) |
| Orbital period | 4.76 days |
| Orbital distance | 0.054 AU |
| Eccentricity | 0.019 |
| Equilibrium temperature | 1,025 K (752 °C) |
| Earth Similarity Index | 0.09 |
| Distance from Earth | 803.6 light-years (246.4 parsecs) |
| Constellation | Eridanus |
| Discovery method | Transit |
| Discovery facility | HATSouth |
| Discovery year | 2014 |
Data: NASA Exoplanet Archive, last updated 2014-05-14. Earth Similarity Index: PHL @ UPR Arecibo.
Frequently Asked Questions About HATS-5 b
Is HATS-5 b habitable?
No — HATS-5 b orbits too close to its star and is too hot for liquid water to exist on its surface.
How far away is HATS-5 b?
HATS-5 b is about 804 light-years from Earth in the constellation Eridanus. A spacecraft traveling as fast as Voyager 1 (about 17 km/s) would need roughly 14,143,360 years to get there.
How big is HATS-5 b compared to Earth?
HATS-5 b has 10.22 times the radius of Earth and about 75.3 times its mass.
How long is a year on HATS-5 b?
One orbit around HATS-5 takes 4.8 Earth days — short enough that 77 of its years would fit into one Earth year.
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