TOI-269 b
TOI-269 b is a mini-Neptune orbiting the M2 V star TOI-269 in the constellation Pictor. It lies about 186 light-years from Earth and was discovered in 2021 using the transit method.
How Big Is TOI-269 b?
TOI-269 b has a radius of 2.77 times that of Earth. Its mass is 8.8 times that of Earth, giving it a density of 2.28 g/cm³ — between that of rocky and gaseous planets.
Is TOI-269 b in the Habitable Zone?
TOI-269 b orbits inside the inner edge of the habitable zone of TOI-269. So close to its star, surface conditions are far too hot for liquid water.
Habitable zone of TOI-269: 0.120–0.312 AU (conservative: 0.152–0.296 AU), per Kopparapu et al. (2014). Earth orbits the Sun at 1 AU.
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Temperature on TOI-269 b
The equilibrium temperature of TOI-269 b is about 531 K (258 °C) — hotter than anywhere on Earth. This estimate ignores any atmosphere, which could change surface temperatures dramatically — Earth's greenhouse effect adds about 33 °C. It receives 19.00 times the stellar energy that Earth gets from the Sun.
Orbit and Year Length
A year on TOI-269 b — one full orbit around TOI-269 — lasts 3.70 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. Its orbit is highly elliptical (eccentricity 0.43), swinging dramatically closer to and farther from its star.
How Was TOI-269 b Discovered?
TOI-269 b was discovered in 2021 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-269 b?
TOI-269 b is 186.0 light-years (57.0 parsecs) from Earth. Light arriving here tonight left the planet around the year 1840. A probe traveling at the speed of Voyager 1 — about 17 km/s, the fastest outbound spacecraft ever launched — would need roughly 3,273,600 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-269 b scores 0.28, ranking #2,369 of 5,568 planets with a known ESI. For reference, Mars scores about 0.70.
The Host Star: TOI-269
TOI-269
- Spectral type
- M2 V
- Surface temperature
- 3,514 K (Sun: 5,772 K)
- Mass
- 0.39 M☉
- Radius
- 0.40 R☉
Planetary System
TOI-269 b is the only planet known to orbit TOI-269 so far.
TOI-269 b — Complete Data
| Radius | 2.770 Earth radii (0.247 Jupiter radii) |
|---|---|
| Mass | 8.80 Earth masses (0.028 Jupiter masses) |
| Density | 2.28 g/cm³ (Earth: 5.51) |
| Orbital period | 3.70 days |
| Orbital distance | 0.035 AU |
| Eccentricity | 0.425 |
| Equilibrium temperature | 531 K (258 °C) |
| Stellar irradiation | 19.00× Earth |
| Earth Similarity Index | 0.28 |
| Distance from Earth | 186.0 light-years (57.0 parsecs) |
| Constellation | Pictor |
| Discovery method | Transit |
| Discovery facility | Transiting Exoplanet Survey Satellite (TESS) |
| Discovery year | 2021 |
Data: NASA Exoplanet Archive, last updated 2021-05-17. Earth Similarity Index: PHL @ UPR Arecibo.
Frequently Asked Questions About TOI-269 b
Is TOI-269 b habitable?
No — TOI-269 b orbits too close to its star and is too hot for liquid water to exist on its surface.
How far away is TOI-269 b?
TOI-269 b is about 186 light-years from Earth in the constellation Pictor. A spacecraft traveling as fast as Voyager 1 (about 17 km/s) would need roughly 3,273,600 years to get there.
How big is TOI-269 b compared to Earth?
TOI-269 b has 2.77 times the radius of Earth and about 8.8 times its mass.
How long is a year on TOI-269 b?
One orbit around TOI-269 takes 3.7 Earth days — short enough that 99 of its years would fit into one Earth year.
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