| 91 Aquarii b | |
| Discoverer: | Mitchell et al. |
| Discovery Site: |  United States |
| Discovered: | 16 November 2013 |
| Discovery Method: | Radial velocity |
| Apsis: | astron |
| Semimajor: | 0.7AU |
| Eccentricity: | 0.027 ± 0.026 |
| Period: | 181.4 ± 0.1 d |
| Time Periastron: | April 11, 2005 2453472.1 ± 24 |
| Arg Peri: | 177.3 ± 0.8 |
| Semi-Amplitude: | 91.0 ± 2.3 |
| Star: | 91 Aquarii |
91 Aquarii b, also known as HD 219449 b, is an extrasolar planet orbiting in the 91 Aquarii system approximately 148 light-years away in the constellation of Aquarius. It orbits at the average distance of 105 Gm from its star, which is slightly closer than Venus is to the sun (108 Gm). The planet takes half an Earth year to orbit around the star in a very circular orbit with eccentricity less than 0.053.