•Can move mass
between stars
•1st (massive) star becomes red giant
•Its
envelope transferred to other star
•Hot
(white dwarf) core exposed
•
•2nd star becomes red giant
•Its
envelope transferred to white dwarf
–Accretion
disk around white dwarf
•Angular
momentum doesn’t let material fall directly to white dwarf surface
–Recurrent
nova explosions
•White
dwarf hot enough for fusion, but no Hydrogen fuel
•New
fuel comes in from companion
•Occasionally
ignites explosively,
blowing away remaining fuel