TOI-2373 b
TOI-2373 b is a cold gas giant orbiting TOI-2373 in the constellation Eridanus. It lies about 1,659 light-years from Earth and was discovered in 2023 using the transit method.
How Big Is TOI-2373 b?
TOI-2373 b has a radius of 10.42 times that of Earth, or 0.93 times the radius of Jupiter. Its mass is 2,956 times that of Earth, giving it a density of 14.40 g/cm³ — comparable to rocky planets like Earth (5.51 g/cm³).
Is TOI-2373 b in the Habitable Zone?
TOI-2373 b orbits inside the inner edge of the habitable zone of TOI-2373. So close to its star, surface conditions are far too hot for liquid water.
Habitable zone of TOI-2373: 0.802–1.896 AU (conservative: 1.016–1.798 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 ›
Temperature on TOI-2373 b
The equilibrium temperature of TOI-2373 b is about 860 K (587 °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-2373 b — one full orbit around TOI-2373 — lasts 13.3 Earth days, shorter than Mercury's 88-day year. It orbits at an average distance of 0.112 AU — closer to its star than Mercury is to the Sun. Its orbit is mildly elliptical (eccentricity 0.11).
How Was TOI-2373 b Discovered?
TOI-2373 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-2373 b?
TOI-2373 b is 1,659.1 light-years (508.7 parsecs) from Earth. Light arriving here tonight left the planet about 1,659 years ago. A probe traveling at the speed of Voyager 1 — about 17 km/s, the fastest outbound spacecraft ever launched — would need roughly 29,200,160 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-2373 b scores 0.10, ranking #4,478 of 5,568 planets with a known ESI. For reference, Mars scores about 0.70.
The Host Star: TOI-2373
TOI-2373
- Surface temperature
- 5,651 K (Sun: 5,772 K)
- Mass
- 1.04 M☉
- Radius
- 1.10 R☉
- Luminosity
- 1.1250 L☉
- Age
- 5.9 billion years (Sun: 4.6)
Planetary System
TOI-2373 b is the only planet known to orbit TOI-2373 so far.
TOI-2373 b — Complete Data
| Radius | 10.424 Earth radii (0.930 Jupiter radii) |
|---|---|
| Mass | 2,955.80 Earth masses (9.300 Jupiter masses) |
| Density | 14.40 g/cm³ (Earth: 5.51) |
| Orbital period | 13.34 days |
| Orbital distance | 0.112 AU |
| Eccentricity | 0.112 |
| Equilibrium temperature | 860 K (587 °C) |
| Earth Similarity Index | 0.10 |
| Distance from Earth | 1,659.1 light-years (508.7 parsecs) |
| Constellation | Eridanus |
| Discovery method | Transit |
| Discovery facility | Transiting Exoplanet Survey Satellite (TESS) |
| Discovery year | 2023 |
Data: NASA Exoplanet Archive, last updated 2023-12-14. Earth Similarity Index: PHL @ UPR Arecibo.
Frequently Asked Questions About TOI-2373 b
Is TOI-2373 b habitable?
No — TOI-2373 b orbits too close to its star and is too hot for liquid water to exist on its surface.
How far away is TOI-2373 b?
TOI-2373 b is about 1,659 light-years from Earth in the constellation Eridanus. A spacecraft traveling as fast as Voyager 1 (about 17 km/s) would need roughly 29,200,160 years to get there.
How big is TOI-2373 b compared to Earth?
TOI-2373 b has 10.42 times the radius of Earth and about 2,956 times its mass.
How long is a year on TOI-2373 b?
One orbit around TOI-2373 takes 13.3 Earth days — short enough that 27 of its years would fit into one Earth year.
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