HATS-37 A b
HATS-37 A b is a hot Jupiter orbiting HATS-37 A in the constellation Hydra. It lies about 691 light-years from Earth and was discovered in 2020 using the transit method.
How Big Is HATS-37 A b?
HATS-37 A b has a radius of 6.79 times that of Earth, or 0.61 times the radius of Jupiter. Its mass is 31.5 times that of Earth, giving it a density of 0.55 g/cm³ — closer to gas planets like Jupiter (1.33 g/cm³).
Is HATS-37 A b in the Habitable Zone?
HATS-37 A b orbits inside the inner edge of the habitable zone of HATS-37 A. So close to its star, surface conditions are far too hot for liquid water.
Habitable zone of HATS-37 A: 0.574–1.371 AU (conservative: 0.727–1.300 AU), per Kopparapu et al. (2014). Earth orbits the Sun at 1 AU.
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Temperature on HATS-37 A b
The equilibrium temperature of HATS-37 A b is about 1,085 K (812 °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 230 times the stellar energy that Earth gets from the Sun.
Orbit and Year Length
A year on HATS-37 A b — one full orbit around HATS-37 A — lasts 4.33 Earth days, shorter than Mercury's 88-day year. It orbits at an average distance of 0.049 AU — closer to its star than Mercury is to the Sun.
How Was HATS-37 A b Discovered?
HATS-37 A 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-37 A b?
HATS-37 A b is 691.1 light-years (211.9 parsecs) from Earth. Light arriving here tonight left the planet around the year 1335. A probe traveling at the speed of Voyager 1 — about 17 km/s, the fastest outbound spacecraft ever launched — would need roughly 12,163,360 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-37 A b scores 0.12, ranking #4,315 of 5,568 planets with a known ESI. For reference, Mars scores about 0.70.
The Host Star: HATS-37 A
HATS-37 A b belongs to a system of 2 stars; it orbits HATS-37 A.
HATS-37 A
- Surface temperature
- 5,326 K (Sun: 5,772 K)
- Mass
- 0.84 M☉
- Radius
- 0.88 R☉
- Luminosity
- 0.5550 L☉
- Age
- 11.5 billion years (Sun: 4.6)
Planetary System
HATS-37 A b is the only planet known to orbit HATS-37 A so far.
HATS-37 A b — Complete Data
| Radius | 6.793 Earth radii (0.606 Jupiter radii) |
|---|---|
| Mass | 31.47 Earth masses (0.099 Jupiter masses) |
| Density | 0.55 g/cm³ (Earth: 5.51) |
| Orbital period | 4.33 days |
| Orbital distance | 0.049 AU |
| Equilibrium temperature | 1,085 K (812 °C) |
| Stellar irradiation | 229.70× Earth |
| Earth Similarity Index | 0.12 |
| Distance from Earth | 691.1 light-years (211.9 parsecs) |
| Constellation | Hydra |
| Discovery method | Transit |
| Discovery facility | HATSouth |
| Discovery year | 2020 |
Data: NASA Exoplanet Archive, last updated 2020-08-06. Earth Similarity Index: PHL @ UPR Arecibo.
Frequently Asked Questions About HATS-37 A b
Is HATS-37 A b habitable?
No — HATS-37 A b orbits too close to its star and is too hot for liquid water to exist on its surface.
How far away is HATS-37 A b?
HATS-37 A b is about 691 light-years from Earth in the constellation Hydra. A spacecraft traveling as fast as Voyager 1 (about 17 km/s) would need roughly 12,163,360 years to get there.
How big is HATS-37 A b compared to Earth?
HATS-37 A b has 6.79 times the radius of Earth and about 31.5 times its mass.
How long is a year on HATS-37 A b?
One orbit around HATS-37 A takes 4.3 Earth days — short enough that 84 of its years would fit into one Earth year.
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