TOI-2443 b
TOI-2443 b is a mini-Neptune orbiting the K5 V star TOI-2443 in the constellation Cetus. It lies about 78 light-years from Earth and was discovered in 2023 using the transit method.
How Big Is TOI-2443 b?
TOI-2443 b has a radius of 2.36 times that of Earth. Its mass is 4.8 times that of Earth, giving it a density of 2.00 g/cm³ — closer to gas planets like Jupiter (1.33 g/cm³).
Is TOI-2443 b in the Habitable Zone?
TOI-2443 b orbits inside the inner edge of the habitable zone of TOI-2443. So close to its star, surface conditions are far too hot for liquid water.
Habitable zone of TOI-2443: 0.297–0.737 AU (conservative: 0.376–0.699 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-2443 b
The equilibrium temperature of TOI-2443 b is about 519 K (246 °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.
Orbit and Year Length
A year on TOI-2443 b — one full orbit around TOI-2443 — lasts 15.7 Earth days, shorter than Mercury's 88-day year. It orbits at an average distance of 0.105 AU — closer to its star than Mercury is to the Sun. Its orbit is highly elliptical (eccentricity 0.30), swinging dramatically closer to and farther from its star.
How Was TOI-2443 b Discovered?
TOI-2443 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-2443 b?
TOI-2443 b is 78.0 light-years (23.9 parsecs) from Earth. Light arriving here tonight left the planet around the year 1948. A probe traveling at the speed of Voyager 1 — about 17 km/s, the fastest outbound spacecraft ever launched — would need roughly 1,372,800 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-2443 b scores 0.31, ranking #1,220 of 5,568 planets with a known ESI. For reference, Mars scores about 0.70.
The Host Star: TOI-2443
TOI-2443
- Spectral type
- K5 V
- Surface temperature
- 4,375 K (Sun: 5,772 K)
- Mass
- 0.64 M☉
- Radius
- 0.63 R☉
- Luminosity
- 0.1365 L☉
- Age
- 7.5 billion years (Sun: 4.6)
Planetary System
TOI-2443 b is the only planet known to orbit TOI-2443 so far.
TOI-2443 b — Complete Data
| Radius | 2.363 Earth radii (0.211 Jupiter radii) |
|---|---|
| Mass | 4.80 Earth masses (0.015 Jupiter masses) |
| Density | 2.00 g/cm³ (Earth: 5.51) |
| Orbital period | 15.67 days |
| Orbital distance | 0.105 AU |
| Eccentricity | 0.301 |
| Equilibrium temperature | 519 K (246 °C) |
| Earth Similarity Index | 0.31 |
| Distance from Earth | 78.0 light-years (23.9 parsecs) |
| Constellation | Cetus |
| Discovery method | Transit |
| Discovery facility | Transiting Exoplanet Survey Satellite (TESS) |
| Discovery year | 2023 |
Data: NASA Exoplanet Archive, last updated 2025-03-10. Earth Similarity Index: PHL @ UPR Arecibo.
Frequently Asked Questions About TOI-2443 b
Is TOI-2443 b habitable?
No — TOI-2443 b orbits too close to its star and is too hot for liquid water to exist on its surface.
How far away is TOI-2443 b?
TOI-2443 b is about 78 light-years from Earth in the constellation Cetus. A spacecraft traveling as fast as Voyager 1 (about 17 km/s) would need roughly 1,372,800 years to get there.
How big is TOI-2443 b compared to Earth?
TOI-2443 b has 2.36 times the radius of Earth and about 4.8 times its mass.
How long is a year on TOI-2443 b?
One orbit around TOI-2443 takes 15.7 Earth days — short enough that 23 of its years would fit into one Earth year.
Explore TOI-2443 b in the app
Browse, filter and compare 6,000+ exoplanets on iPhone, iPad and Apple Watch — with habitable-zone views, widgets and offline data.
