<P> There are roughly 2,000 stars at a distance of up to 50 light - years from the Solar System (64 of them are yellow - orange "G" stars like our Sun). As many as 15% of them can have Earth - sized planets in the habitable zones . </P> <P> On November 4, 2013, astronomers reported, based on Kepler space mission data, that there could be as many as 40 billion Earth - sized planets orbiting in the habitable zones of sun - like stars and red dwarf stars within the Milky Way Galaxy . 11 billion of these estimated planets may be orbiting sun - like stars . The nearest such planet may be as close as 12 light - years away . </P> <P> On August 24, 2016, astronomers announced the discovery of a rocky planet in the habitable zone of Proxima Centauri, the closest star to Earth . Called Proxima b, the planet is 1.3 times the mass of Earth and has an orbital period of roughly 11.2 Earth days . However Proxima Centauri's classification as a red dwarf casts doubts on the habitability of any exoplanets in its orbit due to low stellar flux, high probability of tidal locking, small circumstellar habitable zones and high stellar variation . Another likely candidate is Alpha Centauri, Earth's nearest Sun - like star system 4.37 light years away . Estimates place the probability of finding a habitable planet around Alpha Centauri A or B at roughly 85% . Alpha Centauri is the target of several exoplanet - finding missions, including Breakthrough Starshot and Mission Centaur, the latter of which is chronicled in the 2016 documentary film, "The Search for Earth Proxima ." </P> <Table> <Tr> <Th> Name </Th> <Th> Image (artist's concept) </Th> <Th> </Th> <Th> </Th> <Th> g </Th> <Th> </Th> <Th> </Th> <Th> </Th> <Th> (s) </Th> <Th> </Th> </Tr> <Tr> <Td> Proxima Centauri b </Td> <Td> </Td> <Td> ≥ 1.27 </Td> <Td> ~ 1.1 </Td> <Td> </Td> <Td> 234 K - 39 ° C </Td> <Td> 0.05 </Td> <Td> <0.35 </Td> <Td> </Td> <Td> 4.22 </Td> </Tr> <Tr> <Td> Wolf 1061b </Td> <Td> </Td> <Td> ≥ 1.36 </Td> <Td> ≥ 1.44 </Td> <Td> </Td> <Td> </Td> <Td> </Td> <Td> </Td> <Td> </Td> <Td> 13.8 </Td> </Tr> <Tr> <Td> Wolf 1061c </Td> <Td> </Td> <Td> ≥ 4.3 </Td> <Td> ≥ 1.64 </Td> <Td> </Td> <Td> </Td> <Td> </Td> <Td> </Td> <Td> </Td> <Td> 13.8 </Td> </Tr> <Tr> <Td> Wolf 1061d </Td> <Td> </Td> <Td> ≥ 5.21 </Td> <Td> ≥ 2.04 </Td> <Td> </Td> <Td> </Td> <Td> </Td> <Td> </Td> <Td> </Td> <Td> 13.8 </Td> </Tr> <Tr> <Td> Gliese 876 d </Td> <Td> </Td> <Td> 6.8 </Td> <Td> </Td> <Td> </Td> <Td> 650 K 377 ° C </Td> <Td> 0.021 </Td> <Td> 0.21 </Td> <Td> </Td> <Td> 15 </Td> </Tr> <Tr> <Td> Gliese 682 b </Td> <Td> </Td> <Td> ≥ 2 </Td> <Td> </Td> <Td> </Td> <Td> </Td> <Td> </Td> <Td> </Td> <Td> </Td> <Td> 16 </Td> </Tr> <Tr> <Td> Gliese 832 c </Td> <Td> </Td> <Td> ≥ 5.4 </Td> <Td> </Td> <Td> </Td> <Td> 295 K 22 ° C </Td> <Td> 0.162 </Td> <Td> 0.03 </Td> <Td> </Td> <Td> 16.16 </Td> </Tr> <Tr> <Td> 82 G. Eridani b </Td> <Td> </Td> <Td> ≥ 2.7 </Td> <Td> </Td> <Td> </Td> <Td> 660 K 387 ° C </Td> <Td> 0.1207 </Td> <Td> 0 </Td> <Td> </Td> <Td> 19.71 </Td> </Tr> <Tr> <Td> 82 G. Eridani c </Td> <Td> </Td> <Td> ≥ 2.4 </Td> <Td> </Td> <Td> </Td> <Td> 508 K 235 ° C </Td> <Td> 0.2036 </Td> <Td> 0 </Td> <Td> </Td> <Td> 19.71 </Td> </Tr> <Tr> <Td> 82 G. Eridani d </Td> <Td> </Td> <Td> ≥ 4.8 </Td> <Td> </Td> <Td> </Td> <Td> 388 K 115 ° C </Td> <Td> 0.3499 </Td> <Td> 0 </Td> <Td> </Td> <Td> 19.71 </Td> </Tr> <Tr> <Td> Gliese 581 e </Td> <Td> </Td> <Td> ≥ 1.7 </Td> <Td> </Td> <Td> </Td> <Td> </Td> <Td> 0.029 </Td> <Td> 0 </Td> <Td> </Td> <Td> 20 </Td> </Tr> <Tr> <Td> Gliese 581 c </Td> <Td> </Td> <Td> ≥ 5.6 </Td> <Td> </Td> <Td> </Td> <Td> </Td> <Td> 0.072 </Td> <Td> 0 </Td> <Td> </Td> <Td> 20 </Td> </Tr> <Tr> <Td> Gliese 581 d </Td> <Td> </Td> <Td> ≥ 5.6 </Td> <Td> 2.34 </Td> <Td> 1.27 </Td> <Td> 233 K - 41 ° C </Td> <Td> 0.218 </Td> <Td> 0 </Td> <Td> </Td> <Td> 20 </Td> </Tr> <Tr> <Td> HD 219134 b </Td> <Td> </Td> <Td> 4.5 </Td> <Td> 1.6 </Td> <Td> </Td> <Td> 700 K 427 ° C </Td> <Td> </Td> <Td> </Td> <Td> </Td> <Td> 21 </Td> </Tr> <Tr> <Td> Gliese 667C b </Td> <Td> </Td> <Td> 6.30 </Td> <Td> </Td> <Td> 1.44 </Td> <Td> 445 K <P> 172 ° C </P> </Td> <Td> 0.05 </Td> <Td> 0.09 </Td> <Td> </Td> <Td> 22 </Td> </Tr> <Tr> <Td> Gliese 667C c </Td> <Td> </Td> <Td> 3.8 </Td> <Td> </Td> <Td> 1.32 </Td> <Td> 302 K 29 ° C </Td> <Td> 0.13 </Td> <Td> 0.34 </Td> <Td> </Td> <Td> 22 </Td> </Tr> <Tr> <Td> 61 Virginis b </Td> <Td> </Td> <Td> ≥ 5.1 </Td> <Td> </Td> <Td> </Td> <Td> </Td> <Td> 0.050 </Td> <Td> 0.12 </Td> <Td> </Td> <Td> 28 </Td> </Tr> <Tr> <Td> HD 85512 b </Td> <Td> </Td> <Td> ≥ 3.6 </Td> <Td> 1.74 </Td> <Td> 1.33 </Td> <Td> 351 K 78 ° C </Td> <Td> 0.26 </Td> <Td> 0.11 </Td> <Td> </Td> <Td> 36 </Td> </Tr> <Tr> <Td> GJ 180 b </Td> <Td> </Td> <Td> ≥ 2.3 </Td> <Td> </Td> <Td> </Td> <Td> 312 K 39 ° C </Td> <Td> </Td> <Td> </Td> <Td> </Td> <Td> 38 </Td> </Tr> <Tr> <Td> TRAPPIST - 1b </Td> <Td> </Td> <Td> </Td> <Td> </Td> <Td> </Td> <Td> </Td> <Td> </Td> <Td> </Td> <Td> </Td> <Td> 39.5 </Td> </Tr> <Tr> <Td> TRAPPIST - 1c </Td> <Td> </Td> <Td> </Td> <Td> </Td> <Td> </Td> <Td> </Td> <Td> </Td> <Td> </Td> <Td> </Td> <Td> 39.5 </Td> </Tr> <Tr> <Td> TRAPPIST - 1d </Td> <Td> </Td> <Td> </Td> <Td> </Td> <Td> </Td> <Td> </Td> <Td> </Td> <Td> </Td> <Td> </Td> <Td> 39.5 </Td> </Tr> <Tr> <Td> TRAPPIST - 1e </Td> <Td> </Td> <Td> </Td> <Td> </Td> <Td> </Td> <Td> </Td> <Td> </Td> <Td> </Td> <Td> </Td> <Td> 39.5 </Td> </Tr> <Tr> <Td> TRAPPIST - 1f </Td> <Td> </Td> <Td> </Td> <Td> </Td> <Td> </Td> <Td> </Td> <Td> </Td> <Td> </Td> <Td> </Td> <Td> 39.5 </Td> </Tr> <Tr> <Td> TRAPPIST - 1g </Td> <Td> </Td> <Td> </Td> <Td> </Td> <Td> </Td> <Td> </Td> <Td> </Td> <Td> </Td> <Td> </Td> <Td> 39.5 </Td> </Tr> <Tr> <Td> TRAPPIST - 1h </Td> <Td> </Td> <Td> </Td> <Td> </Td> <Td> </Td> <Td> </Td> <Td> </Td> <Td> </Td> <Td> </Td> <Td> 39.5 </Td> </Tr> <Tr> <Td> 55 Cancri e (Janssen) </Td> <Td> </Td> <Td> 8.6 </Td> <Td> </Td> <Td> </Td> <Td> </Td> <Td> 0.016 </Td> <Td> 0.17 </Td> <Td> </Td> <Td> 40 </Td> </Tr> <Tr> <Td> HD 40307 b </Td> <Td> </Td> <Td> ≥ 4.2 </Td> <Td> </Td> <Td> </Td> <Td> </Td> <Td> 0.047 </Td> <Td> 0.2 </Td> <Td> </Td> <Td> 42 </Td> </Tr> <Tr> <Td> HD 40307 c </Td> <Td> </Td> <Td> ≥ 6.8 </Td> <Td> </Td> <Td> </Td> <Td> </Td> <Td> 0.081 </Td> <Td> 0.06 </Td> <Td> </Td> <Td> 42 </Td> </Tr> <Tr> <Td> HD 40307 d </Td> <Td> </Td> <Td> ≥ 9.2 </Td> <Td> </Td> <Td> </Td> <Td> </Td> <Td> 0.134 </Td> <Td> 0.07 </Td> <Td> </Td> <Td> 42 </Td> </Tr> <Tr> <Td> HD 40307 e </Td> <Td> </Td> <Td> ≥ 3.5 </Td> <Td> </Td> <Td> </Td> <Td> </Td> <Td> 0.1886 </Td> <Td> 0.15 </Td> <Td> </Td> <Td> 42 </Td> </Tr> <Tr> <Td> HD 40307 f </Td> <Td> </Td> <Td> ≥ 5.2 </Td> <Td> </Td> <Td> </Td> <Td> 385 K 112 ° C </Td> <Td> 0.247 </Td> <Td> 0.02 </Td> <Td> </Td> <Td> 42 </Td> </Tr> <Tr> <Td> HD 40307 g </Td> <Td> </Td> <Td> ≥ 7.1 </Td> <Td> </Td> <Td> </Td> <Td> 284 K 11 ° C </Td> <Td> 0.600 </Td> <Td> 0.29 </Td> <Td> </Td> <Td> 42 </Td> </Tr> </Table>

What's the closest habitable planet to earth