NGTS-11 b
NGTS-11 b is a cold gas giant orbiting the K star NGTS-11 in the constellation Cetus. It lies about 621 light-years from Earth and was discovered in 2020 using the transit method.
How Big Is NGTS-11 b?
NGTS-11 b has a radius of 9.16 times that of Earth, or 0.82 times the radius of Jupiter. Its mass is 109 times that of Earth, giving it a density of 0.78 g/cm³ — closer to gas planets like Jupiter (1.33 g/cm³).
Is NGTS-11 b in the Habitable Zone?
NGTS-11 b orbits inside the inner edge of the habitable zone of NGTS-11. So close to its star, surface conditions are far too hot for liquid water.
Habitable zone of NGTS-11: 0.497–1.198 AU (conservative: 0.629–1.136 AU), per Kopparapu et al. (2014). Earth orbits the Sun at 1 AU.
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Temperature on NGTS-11 b
The equilibrium temperature of NGTS-11 b is about 435 K (162 °C) — hotter than anywhere on Earth. 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 NGTS-11 b — one full orbit around NGTS-11 — lasts 35.5 Earth days, shorter than Mercury's 88-day year. It orbits at an average distance of 0.201 AU — closer to its star than Mercury is to the Sun. Its orbit is mildly elliptical (eccentricity 0.13).
How Was NGTS-11 b Discovered?
NGTS-11 b was discovered in 2020 using the transit method, with observations from Transiting Exoplanet Survey Satellite (TESS).
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-11 b?
NGTS-11 b is 621.1 light-years (190.4 parsecs) from Earth. Light arriving here tonight left the planet around the year 1405. A probe traveling at the speed of Voyager 1 — about 17 km/s, the fastest outbound spacecraft ever launched — would need roughly 10,931,360 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-11 b scores 0.19, ranking #3,985 of 5,568 planets with a known ESI. For reference, Mars scores about 0.70.
The Host Star: NGTS-11
NGTS-11
- Spectral type
- K
- Surface temperature
- 5,050 K (Sun: 5,772 K)
- Mass
- 0.86 M☉
- Radius
- 0.83 R☉
- Age
- 3.9 billion years (Sun: 4.6)
Planetary System
NGTS-11 b is the only planet known to orbit NGTS-11 so far.
NGTS-11 b — Complete Data
| Radius | 9.158 Earth radii (0.817 Jupiter radii) |
|---|---|
| Mass | 109.33 Earth masses (0.344 Jupiter masses) |
| Density | 0.78 g/cm³ (Earth: 5.51) |
| Orbital period | 35.46 days |
| Orbital distance | 0.201 AU |
| Eccentricity | 0.130 |
| Equilibrium temperature | 435 K (162 °C) |
| Earth Similarity Index | 0.19 |
| Distance from Earth | 621.1 light-years (190.4 parsecs) |
| Constellation | Cetus |
| Discovery method | Transit |
| Discovery facility | Transiting Exoplanet Survey Satellite (TESS) |
| Discovery year | 2020 |
Data: NASA Exoplanet Archive, last updated 2020-07-02. Earth Similarity Index: PHL @ UPR Arecibo.
Frequently Asked Questions About NGTS-11 b
Is NGTS-11 b habitable?
No — NGTS-11 b orbits too close to its star and is too hot for liquid water to exist on its surface.
How far away is NGTS-11 b?
NGTS-11 b is about 621 light-years from Earth in the constellation Cetus. A spacecraft traveling as fast as Voyager 1 (about 17 km/s) would need roughly 10,931,360 years to get there.
How big is NGTS-11 b compared to Earth?
NGTS-11 b has 9.16 times the radius of Earth and about 109 times its mass.
How long is a year on NGTS-11 b?
One orbit around NGTS-11 takes 35.5 Earth days — short enough that 10 of its years would fit into one Earth year.
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