NGTS-1 b
NGTS-1 b is a hot Jupiter orbiting the M0.5 star NGTS-1 in the constellation Columba. It lies about 711 light-years from Earth and was discovered in 2017 using the transit method.
How Big Is NGTS-1 b?
NGTS-1 b has a radius of 14.91 times that of Earth, or 1.33 times the radius of Jupiter. Its mass is 258 times that of Earth, giving it a density of 0.42 g/cm³ — closer to gas planets like Jupiter (1.33 g/cm³).
Is NGTS-1 b in the Habitable Zone?
NGTS-1 b orbits inside the inner edge of the habitable zone of NGTS-1. So close to its star, surface conditions are far too hot for liquid water.
Habitable zone of NGTS-1: 0.214–0.544 AU (conservative: 0.271–0.515 AU), per Kopparapu et al. (2014). Earth orbits the Sun at 1 AU.
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Temperature on NGTS-1 b
The equilibrium temperature of NGTS-1 b is about 790 K (517 °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 65.30 times the stellar energy that Earth gets from the Sun.
Orbit and Year Length
A year on NGTS-1 b — one full orbit around NGTS-1 — lasts 2.65 Earth days, shorter than Mercury's 88-day year. It orbits at an average distance of 0.033 AU — closer to its star than Mercury is to the Sun. Its orbit is nearly circular (eccentricity 0.016).
How Was NGTS-1 b Discovered?
NGTS-1 b was discovered in 2017 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-1 b?
NGTS-1 b is 711.4 light-years (218.1 parsecs) from Earth. Light arriving here tonight left the planet around the year 1315. A probe traveling at the speed of Voyager 1 — about 17 km/s, the fastest outbound spacecraft ever launched — would need roughly 12,520,640 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-1 b scores 0.08, ranking #4,754 of 5,568 planets with a known ESI. For reference, Mars scores about 0.70.
The Host Star: NGTS-1
NGTS-1
- Spectral type
- M0.5
- Surface temperature
- 3,916 K (Sun: 5,772 K)
- Mass
- 0.62 M☉
- Radius
- 0.57 R☉
Planetary System
NGTS-1 b is the only planet known to orbit NGTS-1 so far.
NGTS-1 b — Complete Data
| Radius | 14.908 Earth radii (1.330 Jupiter radii) |
|---|---|
| Mass | 258.08 Earth masses (0.812 Jupiter masses) |
| Density | 0.42 g/cm³ (Earth: 5.51) |
| Orbital period | 2.65 days |
| Orbital distance | 0.033 AU |
| Eccentricity | 0.016 |
| Equilibrium temperature | 790 K (517 °C) |
| Stellar irradiation | 65.30× Earth |
| Earth Similarity Index | 0.08 |
| Distance from Earth | 711.4 light-years (218.1 parsecs) |
| Constellation | Columba |
| Discovery method | Transit |
| Discovery facility | Next-Generation Transit Survey (NGTS) |
| Discovery year | 2017 |
Data: NASA Exoplanet Archive, last updated 2017-11-09. Earth Similarity Index: PHL @ UPR Arecibo.
Frequently Asked Questions About NGTS-1 b
Is NGTS-1 b habitable?
No — NGTS-1 b orbits too close to its star and is too hot for liquid water to exist on its surface.
How far away is NGTS-1 b?
NGTS-1 b is about 711 light-years from Earth in the constellation Columba. A spacecraft traveling as fast as Voyager 1 (about 17 km/s) would need roughly 12,520,640 years to get there.
How big is NGTS-1 b compared to Earth?
NGTS-1 b has 14.91 times the radius of Earth and about 258 times its mass.
How long is a year on NGTS-1 b?
One orbit around NGTS-1 takes 2.6 Earth days — short enough that 138 of its years would fit into one Earth year.
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