TOI-5543 b
TOI-5543 b is a sub-Neptune orbiting TOI-5543 in the constellation Taurus. It lies about 408 light-years from Earth and was discovered in 2026 using the transit method.
How Big Is TOI-5543 b?
TOI-5543 b has a radius of 3.78 times that of Earth.
Is TOI-5543 b in the Habitable Zone?
The position of TOI-5543 b relative to the habitable zone of TOI-5543 cannot be precisely determined from the available orbital data.
Habitable zone of TOI-5543: 0.512–1.235 AU (conservative: 0.648–1.171 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-5543 b — one full orbit around TOI-5543 — lasts 3.54 Earth days, shorter than Mercury's 88-day year.
How Was TOI-5543 b Discovered?
TOI-5543 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-5543 b?
TOI-5543 b is 408.3 light-years (125.2 parsecs) from Earth. Light arriving here tonight left the planet around the year 1618. A probe traveling at the speed of Voyager 1 — about 17 km/s, the fastest outbound spacecraft ever launched — would need roughly 7,186,080 years to make the journey.
The Host Star: TOI-5543
TOI-5543
- Surface temperature
- 5,058 K (Sun: 5,772 K)
- Mass
- 0.85 M☉
- Radius
- 0.85 R☉
- Luminosity
- 0.4294 L☉
Planetary System
TOI-5543 b is the only planet known to orbit TOI-5543 so far.
TOI-5543 b — Complete Data
| Radius | 3.780 Earth radii (0.337 Jupiter radii) |
|---|---|
| Orbital period | 3.54 days |
| Distance from Earth | 408.3 light-years (125.2 parsecs) |
| Constellation | Taurus |
| Discovery method | Transit |
| Discovery facility | Transiting Exoplanet Survey Satellite (TESS) |
| Discovery year | 2026 |
Data: NASA Exoplanet Archive, last updated 2026-10-08. Earth Similarity Index: PHL @ UPR Arecibo.
Frequently Asked Questions About TOI-5543 b
Is TOI-5543 b habitable?
TOI-5543 b is not known to orbit within the habitable zone of TOI-5543, and as a sub-Neptune it is an unlikely candidate for life as we know it.
How far away is TOI-5543 b?
TOI-5543 b is about 408 light-years from Earth in the constellation Taurus. A spacecraft traveling as fast as Voyager 1 (about 17 km/s) would need roughly 7,186,080 years to get there.
How big is TOI-5543 b compared to Earth?
TOI-5543 b has 3.78 times the radius of Earth.
How long is a year on TOI-5543 b?
One orbit around TOI-5543 takes 3.5 Earth days — short enough that 103 of its years would fit into one Earth year.
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