14.3 Stages in the evolution of a low-mass binary

The more massive star fills its Roche lobe. Mass is transferred to a common envelope. Friction in the common envelope brings the stars closer together. The common envelope is ejected, leaving a white dwarf that is more massive than its normal companion. The companion fills its Roche lobe, beginning a long period of slow mass transfer. Eventually, mass transfer stops and the two stars no longer interact with each other.