The planet is in a circumbinary orbit around the two stars of PSR B1620-26 (which are a pulsar (PSR B1620-26 A) and a white dwarf (WD B1620-26)) and is the first circumbinary planet ever confirmed.
PSR B1620-26c (noto comunemente come Matusalemme) è un pianeta extrasolare, orbitante intorno alla pulsar PSR B1620-26, nell'ammasso globulare M4.