TOI-4559 b
TOI-4559 b is a super-Earth orbiting TOI-4559 in the constellation Hydra. It lies about 103 light-years from Earth and was discovered in 2024 using the transit method.
How Big Is TOI-4559 b?
TOI-4559 b has a radius of 1.42 times that of Earth.
Is TOI-4559 b in the Habitable Zone?
TOI-4559 b orbits inside the inner edge of the habitable zone of TOI-4559. So close to its star, surface conditions are far too hot for liquid water.
Habitable zone of TOI-4559: 0.116–0.301 AU (conservative: 0.147–0.286 AU), per Kopparapu et al. (2014). Earth orbits the Sun at 1 AU.
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Temperature on TOI-4559 b
The equilibrium temperature of TOI-4559 b is about 554 K (281 °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 15.77 times the stellar energy that Earth gets from the Sun.
Orbit and Year Length
A year on TOI-4559 b — one full orbit around TOI-4559 — lasts 3.97 Earth days, shorter than Mercury's 88-day year. It orbits at an average distance of 0.036 AU — closer to its star than Mercury is to the Sun.
How Was TOI-4559 b Discovered?
TOI-4559 b 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-4559 b?
TOI-4559 b is 103.2 light-years (31.6 parsecs) from Earth. Light arriving here tonight left the planet around the year 1923. A probe traveling at the speed of Voyager 1 — about 17 km/s, the fastest outbound spacecraft ever launched — would need roughly 1,816,320 years to make the journey.
The Host Star: TOI-4559
TOI-4559
- Surface temperature
- 3,558 K (Sun: 5,772 K)
- Mass
- 0.39 M☉
- Radius
- 0.37 R☉
- Luminosity
- 0.0203 L☉
- Age
- 7.0 billion years (Sun: 4.6)
Planetary System
TOI-4559 b is the only planet known to orbit TOI-4559 so far.
TOI-4559 b — Complete Data
| Radius | 1.415 Earth radii (0.126 Jupiter radii) |
|---|---|
| Orbital period | 3.97 days |
| Orbital distance | 0.036 AU |
| Equilibrium temperature | 554 K (281 °C) |
| Stellar irradiation | 15.77× Earth |
| Distance from Earth | 103.2 light-years (31.6 parsecs) |
| Constellation | Hydra |
| Discovery method | Transit |
| Discovery facility | Transiting Exoplanet Survey Satellite (TESS) |
| Discovery year | 2024 |
Data: NASA Exoplanet Archive, last updated 2024-04-15. Earth Similarity Index: PHL @ UPR Arecibo.
Frequently Asked Questions About TOI-4559 b
Is TOI-4559 b habitable?
No — TOI-4559 b orbits too close to its star and is too hot for liquid water to exist on its surface.
How far away is TOI-4559 b?
TOI-4559 b is about 103 light-years from Earth in the constellation Hydra. A spacecraft traveling as fast as Voyager 1 (about 17 km/s) would need roughly 1,816,320 years to get there.
How big is TOI-4559 b compared to Earth?
TOI-4559 b has 1.42 times the radius of Earth.
How long is a year on TOI-4559 b?
One orbit around TOI-4559 takes 4.0 Earth days — short enough that 92 of its years would fit into one Earth year.
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