TOI-169 b
TOI-169 b is a hot Jupiter orbiting the G1 V star TOI-169 in the constellation Tucana. It lies about 1,330 light-years from Earth and was discovered in 2020 using the transit method.
How Big Is TOI-169 b?
TOI-169 b has a radius of 12.17 times that of Earth, or 1.09 times the radius of Jupiter. Its mass is 251 times that of Earth, giving it a density of 0.76 g/cm³ — closer to gas planets like Jupiter (1.33 g/cm³).
Is TOI-169 b in the Habitable Zone?
TOI-169 b orbits inside the inner edge of the habitable zone of TOI-169. So close to its star, surface conditions are far too hot for liquid water.
Habitable zone of TOI-169: 0.998–2.344 AU (conservative: 1.264–2.222 AU), per Kopparapu et al. (2014). Earth orbits the Sun at 1 AU.
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Temperature on TOI-169 b
The equilibrium temperature of TOI-169 b is about 1,715 K (1,442 °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 1,443 times the stellar energy that Earth gets from the Sun.
Orbit and Year Length
A year on TOI-169 b — one full orbit around TOI-169 — lasts 2.26 Earth days, shorter than Mercury's 88-day year. It orbits at an average distance of 0.035 AU — closer to its star than Mercury is to the Sun.
How Was TOI-169 b Discovered?
TOI-169 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 TOI-169 b?
TOI-169 b is 1,330.2 light-years (407.8 parsecs) from Earth. Light arriving here tonight left the planet about 1,330 years ago. A probe traveling at the speed of Voyager 1 — about 17 km/s, the fastest outbound spacecraft ever launched — would need roughly 23,411,520 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. TOI-169 b scores 0.07, ranking #4,837 of 5,568 planets with a known ESI. For reference, Mars scores about 0.70.
The Host Star: TOI-169
TOI-169
- Spectral type
- G1 V
- Surface temperature
- 5,880 K (Sun: 5,772 K)
- Mass
- 1.15 M☉
- Radius
- 1.29 R☉
- Luminosity
- 1.7890 L☉
- Age
- 4.7 billion years (Sun: 4.6)
Planetary System
TOI-169 b is the only planet known to orbit TOI-169 so far.
TOI-169 b — Complete Data
| Radius | 12.173 Earth radii (1.086 Jupiter radii) |
|---|---|
| Mass | 251.40 Earth masses (0.791 Jupiter masses) |
| Density | 0.76 g/cm³ (Earth: 5.51) |
| Orbital period | 2.26 days |
| Orbital distance | 0.035 AU |
| Equilibrium temperature | 1,715 K (1,442 °C) |
| Stellar irradiation | 1,443.00× Earth |
| Earth Similarity Index | 0.07 |
| Distance from Earth | 1,330.2 light-years (407.8 parsecs) |
| Constellation | Tucana |
| Discovery method | Transit |
| Discovery facility | Transiting Exoplanet Survey Satellite (TESS) |
| Discovery year | 2020 |
Data: NASA Exoplanet Archive, last updated 2020-07-17. Earth Similarity Index: PHL @ UPR Arecibo.
Frequently Asked Questions About TOI-169 b
Is TOI-169 b habitable?
No — TOI-169 b orbits too close to its star and is too hot for liquid water to exist on its surface.
How far away is TOI-169 b?
TOI-169 b is about 1,330 light-years from Earth in the constellation Tucana. A spacecraft traveling as fast as Voyager 1 (about 17 km/s) would need roughly 23,411,520 years to get there.
How big is TOI-169 b compared to Earth?
TOI-169 b has 12.17 times the radius of Earth and about 251 times its mass.
How long is a year on TOI-169 b?
One orbit around TOI-169 takes 2.3 Earth days — short enough that 162 of its years would fit into one Earth year.
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