TOI-1634 b
TOI-1634 b is a super-Earth orbiting the M2 star TOI-1634 in the constellation Perseus. It lies about 115 light-years from Earth and was discovered in 2021 using the transit method.
How Big Is TOI-1634 b?
TOI-1634 b has a radius of 1.76 times that of Earth. Its mass is 4.9 times that of Earth, giving it a density of 5.28 g/cm³ — comparable to rocky planets like Earth (5.51 g/cm³).
Is TOI-1634 b in the Habitable Zone?
TOI-1634 b orbits inside the inner edge of the habitable zone of TOI-1634. So close to its star, surface conditions are far too hot for liquid water.
Habitable zone of TOI-1634: 0.139–0.360 AU (conservative: 0.176–0.341 AU), per Kopparapu et al. (2014). Earth orbits the Sun at 1 AU.
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Temperature on TOI-1634 b
The equilibrium temperature of TOI-1634 b is about 900 K (627 °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-1634 b — one full orbit around TOI-1634 — lasts just 23.7 hours, shorter than Mercury's 88-day year. It orbits at an average distance of 0.015 AU — closer to its star than Mercury is to the Sun.
How Was TOI-1634 b Discovered?
TOI-1634 b was discovered in 2021 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-1634 b?
TOI-1634 b is 115.0 light-years (35.3 parsecs) from Earth. Light arriving here tonight left the planet around the year 1911. A probe traveling at the speed of Voyager 1 — about 17 km/s, the fastest outbound spacecraft ever launched — would need roughly 2,024,000 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-1634 b scores 0.28, ranking #2,319 of 5,568 planets with a known ESI. For reference, Mars scores about 0.70.
The Host Star: TOI-1634
TOI-1634 b belongs to a system of 2 stars; it orbits TOI-1634.
TOI-1634
- Spectral type
- M2
- Surface temperature
- 3,550 K (Sun: 5,772 K)
- Mass
- 0.50 M☉
- Radius
- 0.45 R☉
- Luminosity
- 0.0289 L☉
The TOI-1634 Planetary System
TOI-1634 b is one of 2 known planets in the TOI-1634 system. Its siblings:
TOI-1634 b — Complete Data
| Radius | 1.759 Earth radii (0.157 Jupiter radii) |
|---|---|
| Mass | 4.90 Earth masses (0.015 Jupiter masses) |
| Density | 5.28 g/cm³ (Earth: 5.51) |
| Orbital period | 0.99 days |
| Orbital distance | 0.015 AU |
| Equilibrium temperature | 900 K (627 °C) |
| Earth Similarity Index | 0.28 |
| Distance from Earth | 115.0 light-years (35.3 parsecs) |
| Constellation | Perseus |
| Discovery method | Transit |
| Discovery facility | Transiting Exoplanet Survey Satellite (TESS) |
| Discovery year | 2021 |
Data: NASA Exoplanet Archive, last updated 2026-04-16. Earth Similarity Index: PHL @ UPR Arecibo.
Frequently Asked Questions About TOI-1634 b
Is TOI-1634 b habitable?
No — TOI-1634 b orbits too close to its star and is too hot for liquid water to exist on its surface.
How far away is TOI-1634 b?
TOI-1634 b is about 115 light-years from Earth in the constellation Perseus. A spacecraft traveling as fast as Voyager 1 (about 17 km/s) would need roughly 2,024,000 years to get there.
How big is TOI-1634 b compared to Earth?
TOI-1634 b has 1.76 times the radius of Earth and about 4.9 times its mass.
How long is a year on TOI-1634 b?
One orbit around TOI-1634 takes 1.0 Earth days — short enough that 369 of its years would fit into one Earth year.
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