TOI-431 c
TOI-431 c is a super-Earth orbiting TOI-431 in the constellation Lepus. It lies about 106 light-years from Earth and was discovered in 2021 using the radial velocity method.
Is TOI-431 c in the Habitable Zone?
TOI-431 c orbits inside the inner edge of the habitable zone of TOI-431. So close to its star, surface conditions are far too hot for liquid water.
Habitable zone of TOI-431: 0.406–0.988 AU (conservative: 0.515–0.937 AU), per Kopparapu et al. (2014). Earth orbits the Sun at 1 AU.
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Temperature on TOI-431 c
The equilibrium temperature of TOI-431 c is about 867 K (594 °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-431 c — one full orbit around TOI-431 — lasts 4.85 Earth days, shorter than Mercury's 88-day year. It orbits at an average distance of 0.052 AU — closer to its star than Mercury is to the Sun.
How Was TOI-431 c Discovered?
TOI-431 c was discovered in 2021 using the radial velocity method, with observations from La Silla Observatory.
The radial velocity method measures the subtle wobble of a star caused by the gravitational pull of an orbiting planet, visible as periodic shifts in the star's light spectrum. The size of the wobble reveals the planet's minimum mass.
How Far Away Is TOI-431 c?
TOI-431 c is 106.2 light-years (32.6 parsecs) from Earth. Light arriving here tonight left the planet around the year 1920. A probe traveling at the speed of Voyager 1 — about 17 km/s, the fastest outbound spacecraft ever launched — would need roughly 1,869,120 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-431 c scores 0.29, ranking #1,673 of 5,568 planets with a known ESI. For reference, Mars scores about 0.70.
The Host Star: TOI-431
TOI-431
- Surface temperature
- 4,850 K (Sun: 5,772 K)
- Mass
- 0.78 M☉
- Radius
- 0.73 R☉
The TOI-431 Planetary System
TOI-431 c is one of 3 known planets in the TOI-431 system. Its siblings:
TOI-431 c — Complete Data
| Mass (best estimate) | 2.83 Earth masses |
|---|---|
| Orbital period | 4.85 days |
| Orbital distance | 0.052 AU |
| Equilibrium temperature | 867 K (594 °C) |
| Earth Similarity Index | 0.29 |
| Distance from Earth | 106.2 light-years (32.6 parsecs) |
| Constellation | Lepus |
| Discovery method | Radial Velocity |
| Discovery facility | La Silla Observatory |
| Discovery year | 2021 |
Data: NASA Exoplanet Archive, last updated 2021-08-16. Earth Similarity Index: PHL @ UPR Arecibo.
Frequently Asked Questions About TOI-431 c
Is TOI-431 c habitable?
No — TOI-431 c orbits too close to its star and is too hot for liquid water to exist on its surface.
How far away is TOI-431 c?
TOI-431 c is about 106 light-years from Earth in the constellation Lepus. A spacecraft traveling as fast as Voyager 1 (about 17 km/s) would need roughly 1,869,120 years to get there.
How long is a year on TOI-431 c?
One orbit around TOI-431 takes 4.8 Earth days — short enough that 75 of its years would fit into one Earth year.
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