TOI-771 b
TOI-771 b is a super-Earth orbiting the M3 star TOI-771 in the constellation Carina. It lies about 82 light-years from Earth and was discovered in 2024 using the transit method.
How Big Is TOI-771 b?
TOI-771 b has a radius of 1.36 times that of Earth. Its mass is 2.5 times that of Earth, giving it a density of 5.40 g/cm³ — comparable to rocky planets like Earth (5.51 g/cm³).
Is TOI-771 b in the Habitable Zone?
TOI-771 b orbits inside the inner edge of the habitable zone of TOI-771. So close to its star, surface conditions are far too hot for liquid water.
Habitable zone of TOI-771: 0.065–0.169 AU (conservative: 0.082–0.160 AU), per Kopparapu et al. (2014). Earth orbits the Sun at 1 AU.
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Temperature on TOI-771 b
The equilibrium temperature of TOI-771 b is about 543 K (270 °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 14.00 times the stellar energy that Earth gets from the Sun.
Orbit and Year Length
A year on TOI-771 b — one full orbit around TOI-771 — lasts 2.33 Earth days, shorter than Mercury's 88-day year. It orbits at an average distance of 0.021 AU — closer to its star than Mercury is to the Sun. Its orbit is mildly elliptical (eccentricity 0.06).
How Was TOI-771 b Discovered?
TOI-771 b was discovered in 2024 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-771 b?
TOI-771 b is 82.4 light-years (25.3 parsecs) from Earth. Light arriving here tonight left the planet around the year 1944. A probe traveling at the speed of Voyager 1 — about 17 km/s, the fastest outbound spacecraft ever launched — would need roughly 1,450,240 years to make the journey.
The Host Star: TOI-771
TOI-771
- Spectral type
- M3
- Surface temperature
- 3,370 K (Sun: 5,772 K)
- Mass
- 0.22 M☉
- Radius
- 0.23 R☉
- Luminosity
- 0.0063 L☉
The TOI-771 Planetary System
TOI-771 b is one of 2 known planets in the TOI-771 system. Its siblings:
- TOI-771 c (Super Earth)
TOI-771 b — Complete Data
| Radius | 1.360 Earth radii (0.121 Jupiter radii) |
|---|---|
| Mass | 2.47 Earth masses (0.008 Jupiter masses) |
| Density | 5.40 g/cm³ (Earth: 5.51) |
| Orbital period | 2.33 days |
| Orbital distance | 0.021 AU |
| Eccentricity | 0.055 |
| Equilibrium temperature | 543 K (270 °C) |
| Stellar irradiation | 14.00× Earth |
| Distance from Earth | 82.4 light-years (25.3 parsecs) |
| Constellation | Carina |
| Discovery method | Transit |
| Discovery facility | Transiting Exoplanet Survey Satellite (TESS) |
| Discovery year | 2024 |
Data: NASA Exoplanet Archive, last updated 2025-05-05. Earth Similarity Index: PHL @ UPR Arecibo.
Frequently Asked Questions About TOI-771 b
Is TOI-771 b habitable?
No — TOI-771 b orbits too close to its star and is too hot for liquid water to exist on its surface.
How far away is TOI-771 b?
TOI-771 b is about 82 light-years from Earth in the constellation Carina. A spacecraft traveling as fast as Voyager 1 (about 17 km/s) would need roughly 1,450,240 years to get there.
How big is TOI-771 b compared to Earth?
TOI-771 b has 1.36 times the radius of Earth and about 2.5 times its mass.
How long is a year on TOI-771 b?
One orbit around TOI-771 takes 2.3 Earth days — short enough that 157 of its years would fit into one Earth year.
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