1. The boundary marking the edge of the sun's influence; the boundary (roughly 100 AU from the sun) between the interplanetary medium and the interstellar medium; where the solar wind from the sun and the radiation from other stars meet
   "Voyager 1 crossed the heliopause in 2012, entering interstellar space"

Derived forms: heliopauses

Type of: bound, boundary, bounds

Encyclopedia: Heliopause