TOI-333 b
TOI-333 b is a Neptune-like planet orbiting TOI-333 in the constellation Phoenix. It lies about 1,149 light-years from Earth and was discovered in 2025 using the transit method.
How Big Is TOI-333 b?
TOI-333 b has a radius of 4.26 times that of Earth. Its mass is 20.1 times that of Earth, giving it a density of 1.42 g/cm³ — closer to gas planets like Jupiter (1.33 g/cm³).
Is TOI-333 b in the Habitable Zone?
TOI-333 b orbits inside the inner edge of the habitable zone of TOI-333. So close to its star, surface conditions are far too hot for liquid water.
Habitable zone of TOI-333: 0.936–2.183 AU (conservative: 1.186–2.070 AU), per Kopparapu et al. (2014). Earth orbits the Sun at 1 AU.
See the full interactive habitable-zone view in the Exoplanet Explorer app ›
Temperature on TOI-333 b
The equilibrium temperature of TOI-333 b is about 1,445 K (1,172 °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 TOI-333 b — one full orbit around TOI-333 — lasts 3.79 Earth days, shorter than Mercury's 88-day year. It orbits at an average distance of 0.049 AU — closer to its star than Mercury is to the Sun.
How Was TOI-333 b Discovered?
TOI-333 b was discovered in 2025 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 TOI-333 b?
TOI-333 b is 1,148.9 light-years (352.3 parsecs) from Earth. Light arriving here tonight left the planet about 1,149 years ago. A probe traveling at the speed of Voyager 1 — about 17 km/s, the fastest outbound spacecraft ever launched — would need roughly 20,220,640 years to make the journey.
The Host Star: TOI-333
TOI-333
- Surface temperature
- 6,241 K (Sun: 5,772 K)
- Mass
- 1.20 M☉
- Radius
- 1.10 R☉
- Age
- 1.0 billion years (Sun: 4.6)
Planetary System
TOI-333 b is the only planet known to orbit TOI-333 so far.
TOI-333 b — Complete Data
| Radius | 4.260 Earth radii (0.380 Jupiter radii) |
|---|---|
| Mass | 20.10 Earth masses (0.063 Jupiter masses) |
| Density | 1.42 g/cm³ (Earth: 5.51) |
| Orbital period | 3.79 days |
| Orbital distance | 0.049 AU |
| Equilibrium temperature | 1,445 K (1,172 °C) |
| Distance from Earth | 1,148.9 light-years (352.3 parsecs) |
| Constellation | Phoenix |
| Discovery method | Transit |
| Discovery facility | Transiting Exoplanet Survey Satellite (TESS) |
| Discovery year | 2025 |
Data: NASA Exoplanet Archive, last updated 2025-12-04. Earth Similarity Index: PHL @ UPR Arecibo.
Frequently Asked Questions About TOI-333 b
Is TOI-333 b habitable?
No — TOI-333 b orbits too close to its star and is too hot for liquid water to exist on its surface.
How far away is TOI-333 b?
TOI-333 b is about 1,149 light-years from Earth in the constellation Phoenix. A spacecraft traveling as fast as Voyager 1 (about 17 km/s) would need roughly 20,220,640 years to get there.
How big is TOI-333 b compared to Earth?
TOI-333 b has 4.26 times the radius of Earth and about 20.1 times its mass.
How long is a year on TOI-333 b?
One orbit around TOI-333 takes 3.8 Earth days — short enough that 96 of its years would fit into one Earth year.
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