HATS-9 b
HATS-9 b is a hot Jupiter orbiting HATS-9 in the constellation Sagittarius. It lies about 2,083 light-years from Earth and was discovered in 2015 using the transit method.
How Big Is HATS-9 b?
HATS-9 b has a radius of 13.85 times that of Earth, or 1.24 times the radius of Jupiter.
Is HATS-9 b in the Habitable Zone?
HATS-9 b orbits inside the inner edge of the habitable zone of HATS-9. So close to its star, surface conditions are far too hot for liquid water.
Habitable zone of HATS-9: 1.111–2.631 AU (conservative: 1.407–2.494 AU), per Kopparapu et al. (2014). Earth orbits the Sun at 1 AU.
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Temperature on HATS-9 b
The equilibrium temperature of HATS-9 b is about 1,746 K (1,473 °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-9 b — one full orbit around HATS-9 — lasts just 46.0 hours, shorter than Mercury's 88-day year. It orbits at an average distance of 0.031 AU — closer to its star than Mercury is to the Sun.
How Was HATS-9 b Discovered?
HATS-9 b was discovered in 2015 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-9 b?
HATS-9 b is 2,083.2 light-years (638.7 parsecs) from Earth. Light arriving here tonight left the planet about 2,083 years ago. A probe traveling at the speed of Voyager 1 — about 17 km/s, the fastest outbound spacecraft ever launched — would need roughly 36,664,320 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-9 b scores 0.07, ranking #5,047 of 5,568 planets with a known ESI. For reference, Mars scores about 0.70.
The Host Star: HATS-9
HATS-9
- Surface temperature
- 5,599 K (Sun: 5,772 K)
- Mass
- 1.10 M☉
- Radius
- 1.56 R☉
Planetary System
HATS-9 b is the only planet known to orbit HATS-9 so far.
HATS-9 b — Complete Data
| Radius | 13.850 Earth radii (1.236 Jupiter radii) |
|---|---|
| Orbital period | 1.92 days |
| Orbital distance | 0.031 AU |
| Equilibrium temperature | 1,746 K (1,473 °C) |
| Earth Similarity Index | 0.07 |
| Distance from Earth | 2,083.2 light-years (638.7 parsecs) |
| Constellation | Sagittarius |
| Discovery method | Transit |
| Discovery facility | HATSouth |
| Discovery year | 2015 |
Data: NASA Exoplanet Archive, last updated 2018-10-24. Earth Similarity Index: PHL @ UPR Arecibo.
Frequently Asked Questions About HATS-9 b
Is HATS-9 b habitable?
No — HATS-9 b orbits too close to its star and is too hot for liquid water to exist on its surface.
How far away is HATS-9 b?
HATS-9 b is about 2,083 light-years from Earth in the constellation Sagittarius. A spacecraft traveling as fast as Voyager 1 (about 17 km/s) would need roughly 36,664,320 years to get there.
How big is HATS-9 b compared to Earth?
HATS-9 b has 13.85 times the radius of Earth.
How long is a year on HATS-9 b?
One orbit around HATS-9 takes 1.9 Earth days — short enough that 191 of its years would fit into one Earth year.
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