HD 212771

HD 212771, also named Lionrock, is a solitary star in the southern zodiac constellation Aquarius. It has an apparent magnitude of 7.60, making it readily visible with binoculars but not the naked eye. Parallax measurements place the object at a distance of 364 light years, and is currently receding with a radial velocity of $$.

HD 212771 has a stellar classification of G8 IV, indicating that it is a subgiant evolving towards the red giant branch after being an F-type main-sequence star for 1.7 billion years. It has 156% the mass of the Sun and 5 times its radius. It radiates at $$ from its slightly enlarged photosphere at an effective temperature of 5,003 K, giving it a yellow-hue. Unlike most planetary hosts, HD 212771 is slightly metal deficient, and spins with a projected rotational velocity of about $11.55$.

Planetary system
In 2010, a group of astronomers at the Keck Observatory surveyed several subgiant stars for extrasolar planets via Doppler spectroscopy They happened to find a massive Jupiter-like planet orbiting HD 212771.

HD 212771 is named Lionrock. The name was selected in the NameExoWorlds campaign by Hong Kong, during the 100th anniversary of the IAU. It is named after the Lion Rock. The planet is named Victoriapeak, after the Victoria Peak.