Gliese 777, often abbreviated as Gl 777 or GJ 777, is a yellow subgiant approximately 52 light-years away in the constellation of Cygnus.
The system is also a binary star system made up of two stars and possibly a third.
As of 2005, two extrasolar planets are known to orbit the primary star.
The primary star of the system (catalogued as Gliese 777A) is a yellow subgiant, a Sun-like star that is ceasing fusing hydrogen in its core.
The star is much older than the Sun, about 6.7 billion years old. It is also rather metal-rich, having about 70% more "metals" (elements heavier than helium) than the Sun, which is typical for stars with extrasolar planets.
The secondary star (Gliese 777B) is a distant, dim red dwarf star orbiting the primary at a distance of 3,000 astronomical units.
One orbit takes at least tens of thousands of years to complete.
The star itself may be a binary, the secondary being a very dim red dwarf.
Not much information is available on the star system.
In 2002 a discovery of a long-period, wide-orbiting planet (Gliese 777b) was announced by the Geneva extrasolar planet search team.
The planet was "Jupiter-twin" and was turned to "eccentric Jupiter" with mass about 1.5 times Jupiter and about the same size.
In 2005 further observation of the star show another amplitude with a period of 17.1 days.