PSR B1620-26 b is an extrasolar planet located approximately 12,400 light-years away from Earth in the constellation of Scorpius (the Scorpion). It bears the unofficial nicknames "Methuselah" and "the Genesis planet" due to its extreme age and a few popular sources refer to this object as "PSR B1620-26 c" (see below for discussion). The planet is in a circumbinary orbit around the two stars of PSR B1620-26 (which comprises a pulsar (PSR B1620-26 A) and a white dwarf (WD B1620-26)). The planet is the oldest known extrasolar planet, believed to be about 12.7 billion years old.
Read more about PSR B1620-26 B: Name, Detection and Discovery, Physical Characteristics