NGTS-12 b
NGTS-12 b is a hot Jupiter orbiting the G star NGTS-12 in the constellation Hydra. It lies about 1,456 light-years from Earth and was discovered in 2020 using the transit method.
How Big Is NGTS-12 b?
NGTS-12 b has a radius of 11.75 times that of Earth, or 1.05 times the radius of Jupiter. Its mass is 66.1 times that of Earth, giving it a density of 0.22 g/cm³ — closer to gas planets like Jupiter (1.33 g/cm³).
Is NGTS-12 b in the Habitable Zone?
NGTS-12 b orbits inside the inner edge of the habitable zone of NGTS-12. So close to its star, surface conditions are far too hot for liquid water.
Habitable zone of NGTS-12: 1.163–2.746 AU (conservative: 1.473–2.603 AU), per Kopparapu et al. (2014). Earth orbits the Sun at 1 AU.
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Temperature on NGTS-12 b
The equilibrium temperature of NGTS-12 b is about 1,257 K (984 °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 416 times the stellar energy that Earth gets from the Sun.
Orbit and Year Length
A year on NGTS-12 b — one full orbit around NGTS-12 — lasts 7.53 Earth days, shorter than Mercury's 88-day year. It orbits at an average distance of 0.076 AU — closer to its star than Mercury is to the Sun.
How Was NGTS-12 b Discovered?
NGTS-12 b was discovered in 2020 using the transit method, with observations from Next-Generation Transit Survey (NGTS).
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 NGTS-12 b?
NGTS-12 b is 1,456.1 light-years (446.4 parsecs) from Earth. Light arriving here tonight left the planet about 1,456 years ago. A probe traveling at the speed of Voyager 1 — about 17 km/s, the fastest outbound spacecraft ever launched — would need roughly 25,627,360 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. NGTS-12 b scores 0.08, ranking #4,711 of 5,568 planets with a known ESI. For reference, Mars scores about 0.70.
The Host Star: NGTS-12
NGTS-12
- Spectral type
- G
- Surface temperature
- 5,690 K (Sun: 5,772 K)
- Mass
- 1.02 M☉
- Radius
- 1.59 R☉
- Age
- 9.4 billion years (Sun: 4.6)
Planetary System
NGTS-12 b is the only planet known to orbit NGTS-12 so far.
NGTS-12 b — Complete Data
| Radius | 11.747 Earth radii (1.048 Jupiter radii) |
|---|---|
| Mass | 66.11 Earth masses (0.208 Jupiter masses) |
| Density | 0.22 g/cm³ (Earth: 5.51) |
| Orbital period | 7.53 days |
| Orbital distance | 0.076 AU |
| Equilibrium temperature | 1,257 K (984 °C) |
| Stellar irradiation | 416.00× Earth |
| Earth Similarity Index | 0.08 |
| Distance from Earth | 1,456.1 light-years (446.4 parsecs) |
| Constellation | Hydra |
| Discovery method | Transit |
| Discovery facility | Next-Generation Transit Survey (NGTS) |
| Discovery year | 2020 |
Data: NASA Exoplanet Archive, last updated 2020-10-16. Earth Similarity Index: PHL @ UPR Arecibo.
Frequently Asked Questions About NGTS-12 b
Is NGTS-12 b habitable?
No — NGTS-12 b orbits too close to its star and is too hot for liquid water to exist on its surface.
How far away is NGTS-12 b?
NGTS-12 b is about 1,456 light-years from Earth in the constellation Hydra. A spacecraft traveling as fast as Voyager 1 (about 17 km/s) would need roughly 25,627,360 years to get there.
How big is NGTS-12 b compared to Earth?
NGTS-12 b has 11.75 times the radius of Earth and about 66.1 times its mass.
How long is a year on NGTS-12 b?
One orbit around NGTS-12 takes 7.5 Earth days — short enough that 48 of its years would fit into one Earth year.
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