Which exoplanet has the shortest year?
Among confirmed rocky exoplanets, KOI-1843.03 has the shortest year known: one full orbit of its star takes about 4.2 hours. Everything about KOI-1843.03 →
The top ten
| # | World | Year length | Distance |
|---|---|---|---|
| ★ 1 | KOI-1843.03 | 4.2 hours | 438 ly |
| 2 | K2-137 b | 4.3 hours | 322 ly |
| 3 | TOI-2431 b | 5.4 hours | 118 ly |
| 4 | TOI-6255 b | 5.7 hours | 66.3 ly |
| 5 | TOI-6324 b | 6.7 hours | 67.0 ly |
| 6 | K2-141 b | 6.7 hours | 202 ly |
| 7 | TOI-4552 b | 7.2 hours | 88.9 ly |
| 8 | GJ 367 b | 7.7 hours | 30.7 ly |
| 9 | TOI-2260 b | 8.5 hours | 330 ly |
| 10 | Kepler-78 b | 8.5 hours | 406 ly |
How we know
This record is scoped to rocky worlds with a real temperature measurement, because the raw catalog's very shortest periods belong to compact-binary artifacts and doubtful rows rather than planets you could stand on. The winner's year is measured directly from its repeating transits, one of the most secure numbers in exoplanet science.
For comparison, the shortest year in our solar system is Mercury's, at 88 days; the worlds on this table finish theirs in hours.
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