HATS-27 b
HATS-27 b is a hot Jupiter orbiting the F star HATS-27 in the constellation Centaurus. It lies about 2,665 light-years from Earth and was discovered in 2016 using the transit method.
How Big Is HATS-27 b?
HATS-27 b has a radius of 16.81 times that of Earth, or 1.50 times the radius of Jupiter. Its mass is 168 times that of Earth, giving it a density of 0.18 g/cm³ — closer to gas planets like Jupiter (1.33 g/cm³).
Is HATS-27 b in the Habitable Zone?
HATS-27 b orbits inside the inner edge of the habitable zone of HATS-27. So close to its star, surface conditions are far too hot for liquid water.
Habitable zone of HATS-27: 1.558–3.621 AU (conservative: 1.974–3.433 AU), per Kopparapu et al. (2014). Earth orbits the Sun at 1 AU.
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Temperature on HATS-27 b
The equilibrium temperature of HATS-27 b is about 1,659 K (1,386 °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-27 b — one full orbit around HATS-27 — lasts 4.64 Earth days, shorter than Mercury's 88-day year. It orbits at an average distance of 0.061 AU — closer to its star than Mercury is to the Sun. Its orbit is highly elliptical (eccentricity 0.58), swinging dramatically closer to and farther from its star.
How Was HATS-27 b Discovered?
HATS-27 b was discovered in 2016 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-27 b?
HATS-27 b is 2,664.7 light-years (817.0 parsecs) from Earth. Light arriving here tonight left the planet about 2,665 years ago. A probe traveling at the speed of Voyager 1 — about 17 km/s, the fastest outbound spacecraft ever launched — would need roughly 46,898,720 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-27 b scores 0.06, ranking #5,230 of 5,568 planets with a known ESI. For reference, Mars scores about 0.70.
The Host Star: HATS-27
HATS-27
- Spectral type
- F
- Surface temperature
- 6,438 K (Sun: 5,772 K)
- Mass
- 1.42 M☉
- Radius
- 1.74 R☉
- Luminosity
- 4.6700 L☉
- Age
- 2.3 billion years (Sun: 4.6)
Planetary System
HATS-27 b is the only planet known to orbit HATS-27 so far.
HATS-27 b — Complete Data
| Radius | 16.814 Earth radii (1.500 Jupiter radii) |
|---|---|
| Mass | 168.45 Earth masses (0.530 Jupiter masses) |
| Density | 0.18 g/cm³ (Earth: 5.51) |
| Orbital period | 4.64 days |
| Orbital distance | 0.061 AU |
| Eccentricity | 0.581 |
| Equilibrium temperature | 1,659 K (1,386 °C) |
| Earth Similarity Index | 0.06 |
| Distance from Earth | 2,664.7 light-years (817.0 parsecs) |
| Constellation | Centaurus |
| Discovery method | Transit |
| Discovery facility | HATSouth |
| Discovery year | 2016 |
Data: NASA Exoplanet Archive, last updated 2016-06-08. Earth Similarity Index: PHL @ UPR Arecibo.
Frequently Asked Questions About HATS-27 b
Is HATS-27 b habitable?
No — HATS-27 b orbits too close to its star and is too hot for liquid water to exist on its surface.
How far away is HATS-27 b?
HATS-27 b is about 2,665 light-years from Earth in the constellation Centaurus. A spacecraft traveling as fast as Voyager 1 (about 17 km/s) would need roughly 46,898,720 years to get there.
How big is HATS-27 b compared to Earth?
HATS-27 b has 16.81 times the radius of Earth and about 168 times its mass.
How long is a year on HATS-27 b?
One orbit around HATS-27 takes 4.6 Earth days — short enough that 79 of its years would fit into one Earth year.
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