TOI-2989 b
TOI-2989 b is a hot Jupiter orbiting the K4 V star TOI-2989 in the constellation Hydra. It lies about 639 light-years from Earth and was discovered in 2025 using the transit method.
How Big Is TOI-2989 b?
TOI-2989 b has a radius of 12.55 times that of Earth, or 1.12 times the radius of Jupiter. Its mass is 953 times that of Earth, giving it a density of 2.70 g/cm³ — between that of rocky and gaseous planets.
Is TOI-2989 b in the Habitable Zone?
TOI-2989 b orbits inside the inner edge of the habitable zone of TOI-2989. So close to its star, surface conditions are far too hot for liquid water.
Habitable zone of TOI-2989: 0.340–0.833 AU (conservative: 0.431–0.790 AU), per Kopparapu et al. (2014). Earth orbits the Sun at 1 AU.
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Temperature on TOI-2989 b
The equilibrium temperature of TOI-2989 b is about 1,001 K (728 °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 124 times the stellar energy that Earth gets from the Sun.
Orbit and Year Length
A year on TOI-2989 b — one full orbit around TOI-2989 — lasts 3.12 Earth days, shorter than Mercury's 88-day year. It orbits at an average distance of 0.038 AU — closer to its star than Mercury is to the Sun.
How Was TOI-2989 b Discovered?
TOI-2989 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-2989 b?
TOI-2989 b is 638.6 light-years (195.8 parsecs) from Earth. Light arriving here tonight left the planet around the year 1388. A probe traveling at the speed of Voyager 1 — about 17 km/s, the fastest outbound spacecraft ever launched — would need roughly 11,239,360 years to make the journey.
The Host Star: TOI-2989
TOI-2989
- Spectral type
- K4 V
- Surface temperature
- 4,672 K (Sun: 5,772 K)
- Mass
- 0.77 M☉
- Radius
- 0.76 R☉
- Luminosity
- 0.1830 L☉
Planetary System
TOI-2989 b is the only planet known to orbit TOI-2989 so far.
TOI-2989 b — Complete Data
| Radius | 12.554 Earth radii (1.120 Jupiter radii) |
|---|---|
| Mass | 953.49 Earth masses (3.000 Jupiter masses) |
| Density | 2.70 g/cm³ (Earth: 5.51) |
| Orbital period | 3.12 days |
| Orbital distance | 0.038 AU |
| Equilibrium temperature | 1,001 K (728 °C) |
| Stellar irradiation | 124.00× Earth |
| Distance from Earth | 638.6 light-years (195.8 parsecs) |
| Constellation | Hydra |
| Discovery method | Transit |
| Discovery facility | Transiting Exoplanet Survey Satellite (TESS) |
| Discovery year | 2025 |
Data: NASA Exoplanet Archive, last updated 2025-06-11. Earth Similarity Index: PHL @ UPR Arecibo.
Frequently Asked Questions About TOI-2989 b
Is TOI-2989 b habitable?
No — TOI-2989 b orbits too close to its star and is too hot for liquid water to exist on its surface.
How far away is TOI-2989 b?
TOI-2989 b is about 639 light-years from Earth in the constellation Hydra. A spacecraft traveling as fast as Voyager 1 (about 17 km/s) would need roughly 11,239,360 years to get there.
How big is TOI-2989 b compared to Earth?
TOI-2989 b has 12.55 times the radius of Earth and about 953 times its mass.
How long is a year on TOI-2989 b?
One orbit around TOI-2989 takes 3.1 Earth days — short enough that 117 of its years would fit into one Earth year.
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