TOI-451 b
TOI-451 b is a super-Earth orbiting the G8 V star TOI-451 in the constellation Eridanus. It lies about 404 light-years from Earth and was discovered in 2020 using the transit method.
How Big Is TOI-451 b?
TOI-451 b has a radius of 1.84 times that of Earth. Its mass is 4.7 times that of Earth, giving it a density of 4.10 g/cm³ — between that of rocky and gaseous planets.
Is TOI-451 b in the Habitable Zone?
TOI-451 b orbits inside the inner edge of the habitable zone of TOI-451. So close to its star, surface conditions are far too hot for liquid water.
Habitable zone of TOI-451: 0.586–1.393 AU (conservative: 0.743–1.321 AU), per Kopparapu et al. (2014). Earth orbits the Sun at 1 AU.
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Temperature on TOI-451 b
The equilibrium temperature of TOI-451 b is about 1,474 K (1,201 °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 786 times the stellar energy that Earth gets from the Sun.
Orbit and Year Length
A year on TOI-451 b — one full orbit around TOI-451 — lasts just 44.6 hours, shorter than Mercury's 88-day year. It orbits at an average distance of 0.027 AU — closer to its star than Mercury is to the Sun.
How Was TOI-451 b Discovered?
TOI-451 b was discovered in 2020 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-451 b?
TOI-451 b is 403.6 light-years (123.7 parsecs) from Earth. Light arriving here tonight left the planet around the year 1623. A probe traveling at the speed of Voyager 1 — about 17 km/s, the fastest outbound spacecraft ever launched — would need roughly 7,103,360 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-451 b scores 0.26, ranking #2,846 of 5,568 planets with a known ESI. For reference, Mars scores about 0.70.
The Host Star: TOI-451
TOI-451 b belongs to a system of 2 stars; it orbits TOI-451.
TOI-451
- Spectral type
- G8 V
- Surface temperature
- 5,490 K (Sun: 5,772 K)
- Mass
- 0.93 M☉
- Radius
- 0.85 R☉
- Luminosity
- 0.5900 L☉
- Age
- 0.1 billion years (Sun: 4.6)
The TOI-451 Planetary System
TOI-451 b is one of 3 known planets in the TOI-451 system. Its siblings:
TOI-451 b — Complete Data
| Radius | 1.840 Earth radii (0.164 Jupiter radii) |
|---|---|
| Mass | 4.70 Earth masses (0.015 Jupiter masses) |
| Density | 4.10 g/cm³ (Earth: 5.51) |
| Orbital period | 1.86 days |
| Orbital distance | 0.027 AU |
| Equilibrium temperature | 1,474 K (1,201 °C) |
| Stellar irradiation | 786.00× Earth |
| Earth Similarity Index | 0.26 |
| Distance from Earth | 403.6 light-years (123.7 parsecs) |
| Constellation | Eridanus |
| Discovery method | Transit |
| Discovery facility | Transiting Exoplanet Survey Satellite (TESS) |
| Discovery year | 2020 |
Data: NASA Exoplanet Archive, last updated 2026-03-19. Earth Similarity Index: PHL @ UPR Arecibo.
Frequently Asked Questions About TOI-451 b
Is TOI-451 b habitable?
No — TOI-451 b orbits too close to its star and is too hot for liquid water to exist on its surface.
How far away is TOI-451 b?
TOI-451 b is about 404 light-years from Earth in the constellation Eridanus. A spacecraft traveling as fast as Voyager 1 (about 17 km/s) would need roughly 7,103,360 years to get there.
How big is TOI-451 b compared to Earth?
TOI-451 b has 1.84 times the radius of Earth and about 4.7 times its mass.
How long is a year on TOI-451 b?
One orbit around TOI-451 takes 1.9 Earth days — short enough that 197 of its years would fit into one Earth year.
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