HATS-72 b
HATS-72 b is a hot Jupiter orbiting HATS-72 in the constellation Aquarius. It lies about 416 light-years from Earth and was discovered in 2020 using the transit method.
How Big Is HATS-72 b?
HATS-72 b has a radius of 8.10 times that of Earth, or 0.72 times the radius of Jupiter. Its mass is 39.9 times that of Earth, giving it a density of 0.41 g/cm³ — closer to gas planets like Jupiter (1.33 g/cm³).
Is HATS-72 b in the Habitable Zone?
HATS-72 b orbits inside the inner edge of the habitable zone of HATS-72. So close to its star, surface conditions are far too hot for liquid water.
Habitable zone of HATS-72: 0.372–0.913 AU (conservative: 0.472–0.866 AU), per Kopparapu et al. (2014). Earth orbits the Sun at 1 AU.
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Temperature on HATS-72 b
The equilibrium temperature of HATS-72 b is about 739 K (466 °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. It receives 49.58 times the stellar energy that Earth gets from the Sun.
Orbit and Year Length
A year on HATS-72 b — one full orbit around HATS-72 — lasts 7.33 Earth days, shorter than Mercury's 88-day year. It orbits at an average distance of 0.067 AU — closer to its star than Mercury is to the Sun. Its orbit is nearly circular (eccentricity 0.013).
How Was HATS-72 b Discovered?
HATS-72 b was discovered in 2020 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-72 b?
HATS-72 b is 416.1 light-years (127.6 parsecs) from Earth. Light arriving here tonight left the planet around the year 1610. A probe traveling at the speed of Voyager 1 — about 17 km/s, the fastest outbound spacecraft ever launched — would need roughly 7,323,360 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-72 b scores 0.13, ranking #4,310 of 5,568 planets with a known ESI. For reference, Mars scores about 0.70.
The Host Star: HATS-72
HATS-72
- Surface temperature
- 4,656 K (Sun: 5,772 K)
- Mass
- 0.73 M☉
- Radius
- 0.72 R☉
- Luminosity
- 0.2193 L☉
- Age
- 12.2 billion years (Sun: 4.6)
Planetary System
HATS-72 b is the only planet known to orbit HATS-72 so far.
HATS-72 b — Complete Data
| Radius | 8.097 Earth radii (0.722 Jupiter radii) |
|---|---|
| Mass | 39.86 Earth masses (0.125 Jupiter masses) |
| Density | 0.41 g/cm³ (Earth: 5.51) |
| Orbital period | 7.33 days |
| Orbital distance | 0.067 AU |
| Eccentricity | 0.013 |
| Equilibrium temperature | 739 K (466 °C) |
| Stellar irradiation | 49.58× Earth |
| Earth Similarity Index | 0.13 |
| Distance from Earth | 416.1 light-years (127.6 parsecs) |
| Constellation | Aquarius |
| Discovery method | Transit |
| Discovery facility | HATSouth |
| Discovery year | 2020 |
Data: NASA Exoplanet Archive, last updated 2020-02-21. Earth Similarity Index: PHL @ UPR Arecibo.
Frequently Asked Questions About HATS-72 b
Is HATS-72 b habitable?
No — HATS-72 b orbits too close to its star and is too hot for liquid water to exist on its surface.
How far away is HATS-72 b?
HATS-72 b is about 416 light-years from Earth in the constellation Aquarius. A spacecraft traveling as fast as Voyager 1 (about 17 km/s) would need roughly 7,323,360 years to get there.
How big is HATS-72 b compared to Earth?
HATS-72 b has 8.10 times the radius of Earth and about 39.9 times its mass.
How long is a year on HATS-72 b?
One orbit around HATS-72 takes 7.3 Earth days — short enough that 50 of its years would fit into one Earth year.
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