The local solar neighborhood is the region of space surrounding the Sun out to a distance of about 100 parsecs (about 300 light years). This volume of space contains roughly a million stars (out of the hundred billion or so in the Milky Way Galaxy). The nearest stars are Proxima Centauri (4.2 light-years), Alpha Centauri A and B (4.3 light-years) to which Proxima may or may not be physically bound, and Barnard's star (6.0 light-years). The brightest star in the sky, Sirius, lies at a distance of 8.6 light-years.