The outer region of a star in which heat is transported mainly by convection. Only stars with masses up to and a little beyond that of the Sun have a convective envelope, in which the gas is cool enough to be only partially ionized. In such a region, as rising gas cools, its electrons and ions recombine, releasing heat which continues to drive the gas upwards. Only 1% of the Sun's mass is in its convective envelope, but in stars of half a solar mass the figure is over 40%.
Subjects: Astronomy and Astrophysics.