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 →
| # | 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 |
| 11 | K2-157 b | 8.8 hours | 973 ly |
| 12 | K2-131 b | 8.9 hours | 497 ly |
| 13 | TOI-2445 b | 8.9 hours | 158 ly |
| 14 | TOI-4527.01 | 9.6 hours | 59.0 ly |
| 15 | TOI-1442 b | 9.8 hours | 134 ly |
| 16 | KOI-4777.01 | 9.9 hours | 562 ly |
| 17 | TOI-1798.02 | 10.5 hours | 369 ly |
| 18 | TOI-561 b | 10.7 hours | 280 ly |
| 19 | TOI-6000 b | 10.8 hours | 247 ly |
| 20 | Kepler-42 c | 10.9 hours | 131 ly |
| 21 | LHS 3844 b | 11.1 hours | 48.5 ly |
| 22 | TOI-1444 b | 11.3 hours | 409 ly |
| 23 | TOI-431 b | 11.8 hours | 106 ly |
| 24 | K2-223 b | 12.1 hours | 648 ly |
| 25 | GJ 1252 b | 12.4 hours | 66.4 ly |
Showing the top 25 of 1,284 that qualify.
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.
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.
How short is the shortest year?
On KOI-1843.03, a full orbit takes 4.2 hours. A person there would live through more than a thousand years in a single Earth year, if the surface were not hot enough to melt.
How close does a planet have to be for a year that short?
Extremely: a few stellar radii, so close that the star fills much of the sky. At that distance a rocky world is tidally locked, its dayside is molten, and its orbit is slowly decaying into the star.
Why is this record scoped to rocky worlds?
Because the very shortest catalogued periods belong to compact binaries and doubtful rows rather than planets. Scoping to rocky worlds with a real temperature keeps the crown on something you could in principle stand on.
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