NGTS-4 b
NGTS-4 b is a super-Earth orbiting NGTS-4 in the constellation Columba. It lies about 915 light-years from Earth and was discovered in 2019 using the transit method.
How Big Is NGTS-4 b?
NGTS-4 b has a radius of 3.18 times that of Earth. Its mass is 20.6 times that of Earth, giving it a density of 3.45 g/cm³ — between that of rocky and gaseous planets.
Is NGTS-4 b in the Habitable Zone?
NGTS-4 b orbits inside the inner edge of the habitable zone of NGTS-4. So close to its star, surface conditions are far too hot for liquid water.
Habitable zone of NGTS-4: 0.518–1.245 AU (conservative: 0.656–1.180 AU), per Kopparapu et al. (2014). Earth orbits the Sun at 1 AU.
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Temperature on NGTS-4 b
The equilibrium temperature of NGTS-4 b is about 1,650 K (1,377 °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 NGTS-4 b — one full orbit around NGTS-4 — lasts just 32.1 hours, shorter than Mercury's 88-day year. It orbits at an average distance of 0.019 AU — closer to its star than Mercury is to the Sun.
How Was NGTS-4 b Discovered?
NGTS-4 b was discovered in 2019 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-4 b?
NGTS-4 b is 915.0 light-years (280.6 parsecs) from Earth. Light arriving here tonight left the planet around the year 1111. A probe traveling at the speed of Voyager 1 — about 17 km/s, the fastest outbound spacecraft ever launched — would need roughly 16,104,000 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-4 b scores 0.20, ranking #3,847 of 5,568 planets with a known ESI. For reference, Mars scores about 0.70.
The Host Star: NGTS-4
NGTS-4
- Surface temperature
- 5,143 K (Sun: 5,772 K)
- Mass
- 0.75 M☉
- Radius
- 0.84 R☉
Planetary System
NGTS-4 b is the only planet known to orbit NGTS-4 so far.
NGTS-4 b — Complete Data
| Radius | 3.180 Earth radii (0.284 Jupiter radii) |
|---|---|
| Mass | 20.60 Earth masses (0.065 Jupiter masses) |
| Density | 3.45 g/cm³ (Earth: 5.51) |
| Orbital period | 1.34 days |
| Orbital distance | 0.019 AU |
| Equilibrium temperature | 1,650 K (1,377 °C) |
| Earth Similarity Index | 0.20 |
| Distance from Earth | 915.0 light-years (280.6 parsecs) |
| Constellation | Columba |
| Discovery method | Transit |
| Discovery facility | Next-Generation Transit Survey (NGTS) |
| Discovery year | 2019 |
Data: NASA Exoplanet Archive, last updated 2019-05-14. Earth Similarity Index: PHL @ UPR Arecibo.
Frequently Asked Questions About NGTS-4 b
Is NGTS-4 b habitable?
No — NGTS-4 b orbits too close to its star and is too hot for liquid water to exist on its surface.
How far away is NGTS-4 b?
NGTS-4 b is about 915 light-years from Earth in the constellation Columba. A spacecraft traveling as fast as Voyager 1 (about 17 km/s) would need roughly 16,104,000 years to get there.
How big is NGTS-4 b compared to Earth?
NGTS-4 b has 3.18 times the radius of Earth and about 20.6 times its mass.
How long is a year on NGTS-4 b?
One orbit around NGTS-4 takes 1.3 Earth days — short enough that 273 of its years would fit into one Earth year.
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