TOI-159 b
TOI-159 b is a hot Jupiter orbiting the F0 V star TOI-159 in the constellation Mensa. It lies about 1,134 light-years from Earth and was discovered in 2026 using the transit method.
How Big Is TOI-159 b?
TOI-159 b has a radius of 18.18 times that of Earth, or 1.62 times the radius of Jupiter. Its mass is 1,110 times that of Earth, giving it a density of 1.02 g/cm³ — closer to gas planets like Jupiter (1.33 g/cm³).
Is TOI-159 b in the Habitable Zone?
The position of TOI-159 b relative to the habitable zone of TOI-159 cannot be precisely determined from the available orbital data.
Temperature on TOI-159 b
The equilibrium temperature of TOI-159 b is about 1,891 K (1,618 °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-159 b — one full orbit around TOI-159 — lasts 3.76 Earth days, shorter than Mercury's 88-day year. It orbits at an average distance of 0.056 AU — closer to its star than Mercury is to the Sun. Its orbit is mildly elliptical (eccentricity 0.24).
How Was TOI-159 b Discovered?
TOI-159 b was discovered in 2026 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-159 b?
TOI-159 b is 1,133.7 light-years (347.6 parsecs) from Earth. Light arriving here tonight left the planet about 1,134 years ago. A probe traveling at the speed of Voyager 1 — about 17 km/s, the fastest outbound spacecraft ever launched — would need roughly 19,953,120 years to make the journey.
The Host Star: TOI-159
TOI-159 b belongs to a system of 2 stars; it orbits TOI-159.
TOI-159
- Spectral type
- F0 V
- Surface temperature
- 7,287 K (Sun: 5,772 K)
- Mass
- 1.66 M☉
- Radius
- 1.62 R☉
- Luminosity
- 6.6400 L☉
- Age
- 0.1 billion years (Sun: 4.6)
Planetary System
TOI-159 b is the only planet known to orbit TOI-159 so far.
TOI-159 b — Complete Data
| Radius | 18.180 Earth radii (1.622 Jupiter radii) |
|---|---|
| Mass | 1,110.00 Earth masses (3.490 Jupiter masses) |
| Density | 1.02 g/cm³ (Earth: 5.51) |
| Orbital period | 3.76 days |
| Orbital distance | 0.056 AU |
| Eccentricity | 0.240 |
| Equilibrium temperature | 1,891 K (1,618 °C) |
| Distance from Earth | 1,133.7 light-years (347.6 parsecs) |
| Constellation | Mensa |
| Discovery method | Transit |
| Discovery facility | Transiting Exoplanet Survey Satellite (TESS) |
| Discovery year | 2026 |
Data: NASA Exoplanet Archive, last updated 2026-05-14. Earth Similarity Index: PHL @ UPR Arecibo.
Frequently Asked Questions About TOI-159 b
Is TOI-159 b habitable?
TOI-159 b is not known to orbit within the habitable zone of TOI-159, and as a hot Jupiter it is an unlikely candidate for life as we know it.
How far away is TOI-159 b?
TOI-159 b is about 1,134 light-years from Earth in the constellation Mensa. A spacecraft traveling as fast as Voyager 1 (about 17 km/s) would need roughly 19,953,120 years to get there.
How big is TOI-159 b compared to Earth?
TOI-159 b has 18.18 times the radius of Earth and about 1,110 times its mass.
How long is a year on TOI-159 b?
One orbit around TOI-159 takes 3.8 Earth days — short enough that 97 of its years would fit into one Earth year.
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