TOI-669 b
TOI-669 b is a super-Earth orbiting TOI-669 in the constellation Sextans. It lies about 466 light-years from Earth and was discovered in 2023 using the transit method.
How Big Is TOI-669 b?
TOI-669 b has a radius of 2.59 times that of Earth. Its mass is 10.0 times that of Earth, giving it a density of 3.17 g/cm³ — between that of rocky and gaseous planets.
Is TOI-669 b in the Habitable Zone?
TOI-669 b orbits inside the inner edge of the habitable zone of TOI-669. So close to its star, surface conditions are far too hot for liquid water.
Habitable zone of TOI-669: 0.706–1.672 AU (conservative: 0.894–1.585 AU), per Kopparapu et al. (2014). Earth orbits the Sun at 1 AU.
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Temperature on TOI-669 b
The equilibrium temperature of TOI-669 b is about 1,125 K (852 °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-669 b — one full orbit around TOI-669 — lasts 3.95 Earth days, shorter than Mercury's 88-day year. It orbits at an average distance of 0.048 AU — closer to its star than Mercury is to the Sun.
How Was TOI-669 b Discovered?
TOI-669 b was discovered in 2023 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-669 b?
TOI-669 b is 466.0 light-years (142.9 parsecs) from Earth. Light arriving here tonight left the planet around the year 1560. A probe traveling at the speed of Voyager 1 — about 17 km/s, the fastest outbound spacecraft ever launched — would need roughly 8,201,600 years to make the journey.
The Host Star: TOI-669
TOI-669
- Surface temperature
- 5,597 K (Sun: 5,772 K)
- Mass
- 0.92 M☉
- Radius
- 0.99 R☉
- Luminosity
- 0.8660 L☉
- Age
- 7.9 billion years (Sun: 4.6)
Planetary System
TOI-669 b is the only planet known to orbit TOI-669 so far.
TOI-669 b — Complete Data
| Radius | 2.586 Earth radii (0.231 Jupiter radii) |
|---|---|
| Mass | 10.00 Earth masses (0.031 Jupiter masses) |
| Density | 3.17 g/cm³ (Earth: 5.51) |
| Orbital period | 3.95 days |
| Orbital distance | 0.048 AU |
| Equilibrium temperature | 1,125 K (852 °C) |
| Distance from Earth | 466.0 light-years (142.9 parsecs) |
| Constellation | Sextans |
| Discovery method | Transit |
| Discovery facility | Transiting Exoplanet Survey Satellite (TESS) |
| Discovery year | 2023 |
Data: NASA Exoplanet Archive, last updated 2024-07-23. Earth Similarity Index: PHL @ UPR Arecibo.
Frequently Asked Questions About TOI-669 b
Is TOI-669 b habitable?
No — TOI-669 b orbits too close to its star and is too hot for liquid water to exist on its surface.
How far away is TOI-669 b?
TOI-669 b is about 466 light-years from Earth in the constellation Sextans. A spacecraft traveling as fast as Voyager 1 (about 17 km/s) would need roughly 8,201,600 years to get there.
How big is TOI-669 b compared to Earth?
TOI-669 b has 2.59 times the radius of Earth and about 10.0 times its mass.
How long is a year on TOI-669 b?
One orbit around TOI-669 takes 3.9 Earth days — short enough that 93 of its years would fit into one Earth year.
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