TOI-2407 b
TOI-2407 b is a Neptune-like planet orbiting TOI-2407 in the constellation Horologium. It lies about 302 light-years from Earth and was discovered in 2025 using the transit method.
How Big Is TOI-2407 b?
TOI-2407 b has a radius of 4.26 times that of Earth.
Is TOI-2407 b in the Habitable Zone?
TOI-2407 b orbits inside the inner edge of the habitable zone of TOI-2407. So close to its star, surface conditions are far too hot for liquid water.
Habitable zone of TOI-2407: 0.173–0.448 AU (conservative: 0.219–0.425 AU), per Kopparapu et al. (2014). Earth orbits the Sun at 1 AU.
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Temperature on TOI-2407 b
The equilibrium temperature of TOI-2407 b is about 705 K (432 °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 41.00 times the stellar energy that Earth gets from the Sun.
Orbit and Year Length
A year on TOI-2407 b — one full orbit around TOI-2407 — lasts 2.70 Earth days, shorter than Mercury's 88-day year. It orbits at an average distance of 0.033 AU — closer to its star than Mercury is to the Sun. Its orbit is mildly elliptical (eccentricity 0.08).
How Was TOI-2407 b Discovered?
TOI-2407 b was discovered in 2025 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-2407 b?
TOI-2407 b is 301.5 light-years (92.4 parsecs) from Earth. Light arriving here tonight left the planet around the year 1725. A probe traveling at the speed of Voyager 1 — about 17 km/s, the fastest outbound spacecraft ever launched — would need roughly 5,306,400 years to make the journey.
The Host Star: TOI-2407
TOI-2407
- Surface temperature
- 3,530 K (Sun: 5,772 K)
- Mass
- 0.55 M☉
- Radius
- 0.57 R☉
- Luminosity
- 0.0448 L☉
Planetary System
TOI-2407 b is the only planet known to orbit TOI-2407 so far.
TOI-2407 b — Complete Data
| Radius | 4.260 Earth radii (0.380 Jupiter radii) |
|---|---|
| Orbital period | 2.70 days |
| Orbital distance | 0.033 AU |
| Eccentricity | 0.080 |
| Equilibrium temperature | 705 K (432 °C) |
| Stellar irradiation | 41.00× Earth |
| Distance from Earth | 301.5 light-years (92.4 parsecs) |
| Constellation | Horologium |
| Discovery method | Transit |
| Discovery facility | Transiting Exoplanet Survey Satellite (TESS) |
| Discovery year | 2025 |
Data: NASA Exoplanet Archive, last updated 2025-06-26. Earth Similarity Index: PHL @ UPR Arecibo.
Frequently Asked Questions About TOI-2407 b
Is TOI-2407 b habitable?
No — TOI-2407 b orbits too close to its star and is too hot for liquid water to exist on its surface.
How far away is TOI-2407 b?
TOI-2407 b is about 302 light-years from Earth in the constellation Horologium. A spacecraft traveling as fast as Voyager 1 (about 17 km/s) would need roughly 5,306,400 years to get there.
How big is TOI-2407 b compared to Earth?
TOI-2407 b has 4.26 times the radius of Earth.
How long is a year on TOI-2407 b?
One orbit around TOI-2407 takes 2.7 Earth days — short enough that 135 of its years would fit into one Earth year.
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