TOI-406 c
TOI-406 c is a super-Earth orbiting the M3 star TOI-406 in the constellation Eridanus. It lies about 101 light-years from Earth and was discovered in 2024 using the transit method.
How Big Is TOI-406 c?
TOI-406 c has a radius of 1.32 times that of Earth. Its mass is 2.1 times that of Earth, giving it a density of 4.90 g/cm³ — comparable to rocky planets like Earth (5.51 g/cm³).
Is TOI-406 c in the Habitable Zone?
TOI-406 c orbits inside the inner edge of the habitable zone of TOI-406. So close to its star, surface conditions are far too hot for liquid water.
Habitable zone of TOI-406: 0.114–0.297 AU (conservative: 0.144–0.281 AU), per Kopparapu et al. (2014). Earth orbits the Sun at 1 AU.
See the full interactive habitable-zone view in the Exoplanet Explorer app ›
Temperature on TOI-406 c
The equilibrium temperature of TOI-406 c is about 584 K (311 °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-406 c — one full orbit around TOI-406 — lasts 3.31 Earth days, shorter than Mercury's 88-day year. It orbits at an average distance of 0.032 AU — closer to its star than Mercury is to the Sun. Its orbit is nearly circular (eccentricity 0.032).
How Was TOI-406 c Discovered?
TOI-406 c 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-406 c?
TOI-406 c is 101.3 light-years (31.1 parsecs) from Earth. Light arriving here tonight left the planet around the year 1925. A probe traveling at the speed of Voyager 1 — about 17 km/s, the fastest outbound spacecraft ever launched — would need roughly 1,782,880 years to make the journey.
The Host Star: TOI-406
TOI-406
- Spectral type
- M3
- Surface temperature
- 3,392 K (Sun: 5,772 K)
- Mass
- 0.41 M☉
- Radius
- 0.41 R☉
- Luminosity
- 0.0193 L☉
The TOI-406 Planetary System
TOI-406 c is one of 2 known planets in the TOI-406 system. Its siblings:
- TOI-406.01 (Super Earth)
TOI-406 c — Complete Data
| Radius | 1.320 Earth radii (0.118 Jupiter radii) |
|---|---|
| Mass | 2.08 Earth masses (0.007 Jupiter masses) |
| Density | 4.90 g/cm³ (Earth: 5.51) |
| Orbital period | 3.31 days |
| Orbital distance | 0.032 AU |
| Eccentricity | 0.032 |
| Equilibrium temperature | 584 K (311 °C) |
| Stellar irradiation | 19.00× Earth |
| Distance from Earth | 101.3 light-years (31.1 parsecs) |
| Constellation | Eridanus |
| Discovery method | Transit |
| Discovery facility | Transiting Exoplanet Survey Satellite (TESS) |
| Discovery year | 2024 |
Data: NASA Exoplanet Archive, last updated 2024-12-16. Earth Similarity Index: PHL @ UPR Arecibo.
Frequently Asked Questions About TOI-406 c
Is TOI-406 c habitable?
No — TOI-406 c orbits too close to its star and is too hot for liquid water to exist on its surface.
How far away is TOI-406 c?
TOI-406 c is about 101 light-years from Earth in the constellation Eridanus. A spacecraft traveling as fast as Voyager 1 (about 17 km/s) would need roughly 1,782,880 years to get there.
How big is TOI-406 c compared to Earth?
TOI-406 c has 1.32 times the radius of Earth and about 2.1 times its mass.
How long is a year on TOI-406 c?
One orbit around TOI-406 takes 3.3 Earth days — short enough that 110 of its years would fit into one Earth year.
Explore TOI-406 c in the app
Browse, filter and compare 6,000+ exoplanets on iPhone, iPad and Apple Watch — with habitable-zone views, widgets and offline data.
