TOI-5800 b
TOI-5800 b is a super-Earth orbiting the K3 V star TOI-5800 in the constellation Aquila. It lies about 140 light-years from Earth and was discovered in 2025 using the transit method.
How Big Is TOI-5800 b?
TOI-5800 b has a radius of 2.46 times that of Earth. Its mass is 9.5 times that of Earth, giving it a density of 3.46 g/cm³ — between that of rocky and gaseous planets.
Is TOI-5800 b in the Habitable Zone?
TOI-5800 b orbits inside the inner edge of the habitable zone of TOI-5800. So close to its star, surface conditions are far too hot for liquid water.
Habitable zone of TOI-5800: 0.438–1.066 AU (conservative: 0.555–1.011 AU), per Kopparapu et al. (2014). Earth orbits the Sun at 1 AU.
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Temperature on TOI-5800 b
The equilibrium temperature of TOI-5800 b is about 1,108 K (835 °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-5800 b — one full orbit around TOI-5800 — lasts 2.63 Earth days, shorter than Mercury's 88-day year. It orbits at an average distance of 0.034 AU — closer to its star than Mercury is to the Sun. Its orbit is highly elliptical (eccentricity 0.30), swinging dramatically closer to and farther from its star.
How Was TOI-5800 b Discovered?
TOI-5800 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-5800 b?
TOI-5800 b is 139.9 light-years (42.9 parsecs) from Earth. Light arriving here tonight left the planet around the year 1887. A probe traveling at the speed of Voyager 1 — about 17 km/s, the fastest outbound spacecraft ever launched — would need roughly 2,462,240 years to make the journey.
The Host Star: TOI-5800
TOI-5800
- Spectral type
- K3 V
- Surface temperature
- 4,850 K (Sun: 5,772 K)
- Mass
- 0.78 M☉
- Radius
- 0.77 R☉
- Luminosity
- 0.3090 L☉
- Age
- 8.1 billion years (Sun: 4.6)
Planetary System
TOI-5800 b is the only planet known to orbit TOI-5800 so far.
TOI-5800 b — Complete Data
| Radius | 2.460 Earth radii (0.219 Jupiter radii) |
|---|---|
| Mass | 9.50 Earth masses (0.030 Jupiter masses) |
| Density | 3.46 g/cm³ (Earth: 5.51) |
| Orbital period | 2.63 days |
| Orbital distance | 0.034 AU |
| Eccentricity | 0.300 |
| Equilibrium temperature | 1,108 K (835 °C) |
| Distance from Earth | 139.9 light-years (42.9 parsecs) |
| Constellation | Aquila |
| Discovery method | Transit |
| Discovery facility | Transiting Exoplanet Survey Satellite (TESS) |
| Discovery year | 2025 |
Data: NASA Exoplanet Archive, last updated 2025-08-14. Earth Similarity Index: PHL @ UPR Arecibo.
Frequently Asked Questions About TOI-5800 b
Is TOI-5800 b habitable?
No — TOI-5800 b orbits too close to its star and is too hot for liquid water to exist on its surface.
How far away is TOI-5800 b?
TOI-5800 b is about 140 light-years from Earth in the constellation Aquila. A spacecraft traveling as fast as Voyager 1 (about 17 km/s) would need roughly 2,462,240 years to get there.
How big is TOI-5800 b compared to Earth?
TOI-5800 b has 2.46 times the radius of Earth and about 9.5 times its mass.
How long is a year on TOI-5800 b?
One orbit around TOI-5800 takes 2.6 Earth days — short enough that 139 of its years would fit into one Earth year.
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