| Extrasolarplanet: | yes |
| G 9-40 b | |
| Image Scale: | 1.25 |
| Apsis: | astron |
| Discovered: | December 2019 |
| Discovery Method: | radial velocity and transit |
| Alt Names: | K2-313 b |
| Eccentricity: | 0 |
| Single Temperature: | (440.6K, equilibrium) |
G 9-40 b is a sub-Neptune exoplanet that has an orbital period of 5.7 days. The host star is a red dwarf located 91lk=onNaNlk=on away from Earth in the constellation Cancer. The planet was discovered in 2019.[1] [2] The planet's density is too low for a rocky composition, suggesting that it is either water-rich or has a significant hydrogen atmosphere.