HATS-61 b
HATS-61 b is a hot Jupiter orbiting HATS-61 in the constellation Eridanus. It lies about 2,217 light-years from Earth and was discovered in 2018 using the transit method.
How Big Is HATS-61 b?
HATS-61 b has a radius of 13.39 times that of Earth, or 1.20 times the radius of Jupiter. Its mass is 1,081 times that of Earth, giving it a density of 2.47 g/cm³ — between that of rocky and gaseous planets.
Is HATS-61 b in the Habitable Zone?
HATS-61 b orbits inside the inner edge of the habitable zone of HATS-61. So close to its star, surface conditions are far too hot for liquid water.
Habitable zone of HATS-61: 1.164–2.761 AU (conservative: 1.474–2.618 AU), per Kopparapu et al. (2014). Earth orbits the Sun at 1 AU.
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Temperature on HATS-61 b
The equilibrium temperature of HATS-61 b is about 1,226 K (953 °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 374 times the stellar energy that Earth gets from the Sun.
Orbit and Year Length
A year on HATS-61 b — one full orbit around HATS-61 — lasts 7.82 Earth days, shorter than Mercury's 88-day year. It orbits at an average distance of 0.079 AU — closer to its star than Mercury is to the Sun. Its orbit is mildly elliptical (eccentricity 0.09).
How Was HATS-61 b Discovered?
HATS-61 b was discovered in 2018 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-61 b?
HATS-61 b is 2,217.1 light-years (679.8 parsecs) from Earth. Light arriving here tonight left the planet about 2,217 years ago. A probe traveling at the speed of Voyager 1 — about 17 km/s, the fastest outbound spacecraft ever launched — would need roughly 39,020,960 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-61 b scores 0.07, ranking #4,950 of 5,568 planets with a known ESI. For reference, Mars scores about 0.70.
The Host Star: HATS-61
HATS-61
- Surface temperature
- 5,542 K (Sun: 5,772 K)
- Mass
- 1.08 M☉
- Radius
- 1.66 R☉
- Luminosity
- 2.3400 L☉
- Age
- 8.9 billion years (Sun: 4.6)
Planetary System
HATS-61 b is the only planet known to orbit HATS-61 so far.
HATS-61 b — Complete Data
| Radius | 13.395 Earth radii (1.195 Jupiter radii) |
|---|---|
| Mass | 1,080.62 Earth masses (3.400 Jupiter masses) |
| Density | 2.47 g/cm³ (Earth: 5.51) |
| Orbital period | 7.82 days |
| Orbital distance | 0.079 AU |
| Eccentricity | 0.092 |
| Equilibrium temperature | 1,226 K (953 °C) |
| Stellar irradiation | 374.20× Earth |
| Earth Similarity Index | 0.07 |
| Distance from Earth | 2,217.1 light-years (679.8 parsecs) |
| Constellation | Eridanus |
| Discovery method | Transit |
| Discovery facility | HATSouth |
| Discovery year | 2018 |
Data: NASA Exoplanet Archive, last updated 2024-07-12. Earth Similarity Index: PHL @ UPR Arecibo.
Frequently Asked Questions About HATS-61 b
Is HATS-61 b habitable?
No — HATS-61 b orbits too close to its star and is too hot for liquid water to exist on its surface.
How far away is HATS-61 b?
HATS-61 b is about 2,217 light-years from Earth in the constellation Eridanus. A spacecraft traveling as fast as Voyager 1 (about 17 km/s) would need roughly 39,020,960 years to get there.
How big is HATS-61 b compared to Earth?
HATS-61 b has 13.39 times the radius of Earth and about 1,081 times its mass.
How long is a year on HATS-61 b?
One orbit around HATS-61 takes 7.8 Earth days — short enough that 47 of its years would fit into one Earth year.
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