At a distance of 2.6 parsecs (8.6 ly), the Sirius system contains two of the eight nearest stars to the Solar System (not including the Sun),[87] and is the fifth closest stellar system to ours (again not including the Sun).[87] This proximity is the main reason for its brightness, as with other near stars such as Alpha Centauri and in stark contrast to distant, highly luminous supergiants such as Canopus, Rigel or Betelgeuse.[88] However, it is still around 25 times more luminous than the Sun.[12] The closest large neighbouring star to Sirius is Procyon, 1.61 parsecs (5.24 ly) away.[89] The Voyager 2 spacecraft, launched in 1977 to study the four Jovian planets in the Solar System, is expected to pass within 4.3 light-years (1.3 pc) of Sirius in approximately 296,000 years.[90]