Which exoplanet has the longest year?
The confirmed exoplanet with the longest year is COCONUTS-2 b: a single orbit of its star takes about 1,100,616 years. Everything about COCONUTS-2 b →
The top ten
| # | World | Year length | Distance |
|---|---|---|---|
| ★ 1 | COCONUTS-2 b | 1,100,616 years | 35.5 ly |
| 2 | CFHTWIR-Oph 98 b | 22,012 years | distance unknown |
| 3 | Oph 11 b | 19,986 years | 444 ly |
| 4 | VHS J125601.92-125723.9 b | 15,880 years | 41.4 ly |
| 5 | b Cen AB b | 4,901 years | 320 ly |
| 6 | HR 8799 b | 465 years | 135 ly |
| 7 | HD 143811 AB b | 320 years | 446 ly |
| 8 | HIP 81208 C b | 285 years | 481 ly |
| 9 | Pluto | 248 years | 0.0 ly |
| 10 | Charon | 248 years | 0.0 ly |
How we know
The longest confirmed years belong to worlds orbiting so far out that no one has ever watched them complete a single orbit: the period comes from the physics of the measured orbit rather than a stopwatch. Disputed rows are excluded.
For comparison, Neptune takes about 165 years to circle the Sun; the worlds on this table make that look brisk. What could unseat this record: directly imaged giants at extreme separations, whose orbits are pinned down a fraction at a time.
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