| Gliese 777 c | |
| Discoverer: | Marcy et al. |
| Discovery Site: | United States |
| Discovered: | 24 June 2005 |
| Apsis: | astron |
| Aphelion: | 0.129AU |
| Perihelion: | 0.127AU |
| Semimajor: | 0.128± |
| Eccentricity: | 0.01 ± 0.1 |
| Period: | 17.1 ± 0.015 d 0.047 y |
| Time Periastron: | 2,450,000.07 ± 0.9 |
| Arg Peri: | 153.7 ± 32 |
| Semi-Amplitude: | 4.6 ± 1.1 |
| Single Temperature: | ~717 |
Gliese 777 c, often catalogued as Gliese 777 Ac or simply HD 190360 c, is an extrasolar planet approximately 52 light-years away in the constellation of Cygnus. The planet was discovered orbiting the primary star of the Gliese 777 system in 2005 using the radial velocity method and confirmed in 2009. The planet was once called the "smallest extrasolar planet discovered", but this is currently no longer the case. With a minimum mass just 18 times that of the Earth, the planet is likely a "hot Neptune" planet, a small Jovian planet, or possibly a large terrestrial planet (a super-Earth).