TOI-4551 b
TOI-4551 b is a hot Jupiter orbiting TOI-4551 in the constellation Hydra. It lies about 705 light-years from Earth and was discovered in 2023 using the transit method.
How Big Is TOI-4551 b?
TOI-4551 b has a radius of 11.86 times that of Earth, or 1.06 times the radius of Jupiter. Its mass is 474 times that of Earth, giving it a density of 1.74 g/cm³ — closer to gas planets like Jupiter (1.33 g/cm³).
Is TOI-4551 b in the Habitable Zone?
TOI-4551 b orbits inside the inner edge of the habitable zone of TOI-4551. So close to its star, surface conditions are far too hot for liquid water.
Habitable zone of TOI-4551: 1.983–4.815 AU (conservative: 2.512–4.566 AU), per Kopparapu et al. (2014). Earth orbits the Sun at 1 AU.
See the full interactive habitable-zone view in the Exoplanet Explorer app ›
Orbit and Year Length
A year on TOI-4551 b — one full orbit around TOI-4551 — lasts 9.96 Earth days, shorter than Mercury's 88-day year. It orbits at an average distance of 0.099 AU — closer to its star than Mercury is to the Sun. Its orbit is mildly elliptical (eccentricity 0.10).
How Was TOI-4551 b Discovered?
TOI-4551 b was discovered in 2023 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-4551 b?
TOI-4551 b is 704.5 light-years (216.0 parsecs) from Earth. Light arriving here tonight left the planet around the year 1322. A probe traveling at the speed of Voyager 1 — about 17 km/s, the fastest outbound spacecraft ever launched — would need roughly 12,399,200 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-4551 b scores 0.08, ranking #4,762 of 5,568 planets with a known ESI. For reference, Mars scores about 0.70.
The Host Star: TOI-4551
TOI-4551
- Surface temperature
- 4,896 K (Sun: 5,772 K)
- Mass
- 1.31 M☉
- Radius
- 3.55 R☉
- Luminosity
- 6.3499 L☉
- Age
- 4.9 billion years (Sun: 4.6)
Planetary System
TOI-4551 b is the only planet known to orbit TOI-4551 so far.
TOI-4551 b — Complete Data
| Radius | 11.859 Earth radii (1.058 Jupiter radii) |
|---|---|
| Mass | 473.56 Earth masses (1.490 Jupiter masses) |
| Density | 1.74 g/cm³ (Earth: 5.51) |
| Orbital period | 9.96 days |
| Orbital distance | 0.099 AU |
| Eccentricity | 0.101 |
| Earth Similarity Index | 0.08 |
| Distance from Earth | 704.5 light-years (216.0 parsecs) |
| Constellation | Hydra |
| Discovery method | Transit |
| Discovery facility | Transiting Exoplanet Survey Satellite (TESS) |
| Discovery year | 2023 |
Data: NASA Exoplanet Archive, last updated 2023-11-29. Earth Similarity Index: PHL @ UPR Arecibo.
Frequently Asked Questions About TOI-4551 b
Is TOI-4551 b habitable?
No — TOI-4551 b orbits too close to its star and is too hot for liquid water to exist on its surface.
How far away is TOI-4551 b?
TOI-4551 b is about 705 light-years from Earth in the constellation Hydra. A spacecraft traveling as fast as Voyager 1 (about 17 km/s) would need roughly 12,399,200 years to get there.
How big is TOI-4551 b compared to Earth?
TOI-4551 b has 11.86 times the radius of Earth and about 474 times its mass.
How long is a year on TOI-4551 b?
One orbit around TOI-4551 takes 10.0 Earth days — short enough that 37 of its years would fit into one Earth year.
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