What is the coldest known rocky planet?
The coldest rocky exoplanet with a measured temperature is GJ 3323 c, at about -125°C (-194°F): colder than any place on Mars, and the coldest solid ground the catalog can actually put a number on. Everything about GJ 3323 c →
| # | World | Equilibrium temp | Distance |
|---|---|---|---|
| ★ 1 | GJ 3323 c | -125°C (-194°F) | 17.5 ly |
| 2 | Teegarden's Star d | -114°C (-173°F) | 12.5 ly |
| 3 | TRAPPIST-1 h | -101°C (-151°F) | 40.5 ly |
| 4 | GJ 1002 c | -91°C (-133°F) | 15.8 ly |
| 5 | Kepler-441 b | -84°C (-119°F) | 874 ly |
| 6 | TRAPPIST-1 g | -76°C (-105°F) | 40.5 ly |
| 7 | Kepler-62 f | -65°C (-85°F) | 981 ly |
| 8 | Teegarden's Star c | -64°C (-83°F) | 12.5 ly |
| 9 | Kepler-1229 b | -61°C (-78°F) | 866 ly |
| 10 | Gl 725 B c | -58°C (-73°F) | 22.3 ly |
| 11 | TRAPPIST-1 f | -55°C (-68°F) | 40.5 ly |
| 12 | Proxima Cen b | -55°C (-67°F) | 4.2 ly |
| 13 | GJ 1002 b | -42°C (-44°F) | 15.8 ly |
| 14 | Kepler-1649 c | -39°C (-38°F) | 301 ly |
| 15 | TOI-715 b | -39°C (-38°F) | 138 ly |
| 16 | Kepler-442 b | -32°C (-26°F) | 1,194 ly |
| 17 | GJ 1061 d | -31°C (-24°F) | 12.0 ly |
| 18 | TRAPPIST-1 e | -23°C (-10°F) | 40.5 ly |
| 19 | Wolf 1069 b | -23°C (-9°F) | 31.3 ly |
| 20 | Kepler-1652 b | -5°C (23°F) | 822 ly |
| 21 | TOI-700 d | -4°C (24°F) | 102 ly |
| 22 | Kepler-62 e | -3°C (26°F) | 981 ly |
| 23 | GJ 3378 b | -1°C (30°F) | 25.2 ly |
| 24 | LP 890-9 c | -1°C (30°F) | 106 ly |
| 25 | TOI-700 e | 0°C (32°F) | 102 ly |
Showing the top 25 of 1,273 that qualify.
The coldest world here is around 150 K, which is cold by any human standard and warm next to the outer solar system: Pluto averages about 44 K. That gap is a statement about our instruments, not about the universe. Genuinely frozen exoplanets exist and are found by microlensing, but those detections give a mass and a separation without the stellar measurements an equilibrium temperature needs, so they carry no temperature at all and cannot be ranked.
What this table actually holds is the outer planets of nearby red dwarf systems: worlds far enough from a dim star to sit below freezing, close enough that a wobble or a transit could find them. The floor is 30 K, because nothing sits below the 2.7 K glow left over from the Big Bang and a catalogued value beneath 30 K is a placeholder rather than a measurement. Our own solar system's frozen bodies are excluded: they are moons and dwarf planets, not exoplanets.
What is the coldest known rocky planet?
The coldest rocky exoplanet with a measured temperature is GJ 3323 c, at about -125°C (-194°F): colder than any place on Mars, and the coldest solid ground the catalog can actually put a number on.
How cold is the coldest rocky planet?
GJ 3323 c sits at about -125°C (-194°F) as an equilibrium temperature, which is the balance point starlight alone can hold it at. Mars, for comparison, averages about −60°C, and Pluto around −230°C.
Could anything survive on a world that cold?
Not on the surface as it stands. Water is locked up as ice and chemistry runs very slowly. The interesting case is underneath: a frozen world can hold liquid water deep below, warmed by its own internal heat and by tides, which is what makes moons like Europa and Enceladus worth visiting despite surfaces far below freezing. A thick enough atmosphere would also warm the surface well above the equilibrium temperature quoted here.
Why are cold planets so rare in the catalog?
Because our two main detection methods both need a planet close to its star. A transit requires the planet to cross the star from our point of view, which becomes vanishingly unlikely on a wide orbit, and a wobble takes as long to measure as the planet's year. Distant, cold worlds are the hardest thing to find, not the rarest thing to exist: our own solar system is mostly made of them.
Keep exploring: all records · the coldest planet of any kind · how microlensing finds planets