Parasite common envelope evolution by triple-star systems

ABSTRACT We study a scenario in which giant wide tertiary star engulfs and forces tight binary system of white dwarf (WD) main-sequence (MS) to enter common envelope evolution (CEE) with each other, then unbinds the WD–MS envelope. The system, now WD inside MS envelope, does not have sufficient orbital energy unbind their However, as they approach centre Roche lobe overflow core and/or merger remove large fraction or all it. Namely, source for unbinding is triple-star CEE. For that, we term this parasite Overall, destruction absorbs from process that might lead WD–core during CEE leaves behind either one massive some cases explode peculiar Type Ia supernova two close WDs at later time supernova. very crudely estimate rate be ≈0.001 out evolved triple stars.