XO-2 is a binary star system about 490 light-years (150 parsecs) away in the constellation Lynx.
The system has a magnitude of 11 and cannot be seen with the naked eye but is visible through a small telescope.
XO-2Nb, which is classified as a hot Jupiter, was discovered by the XO Telescope using the transit method around XO-2N in 2007.
[3] A long-period variation in the radial velocity of XO-2N was detected in 2015, which could be explained by either a second planet or a stellar activity cycle.
[9] A 2024 study found evidence for a third, super-Jupiter mass planet around XO-2S.