Grazing envelope evolution towards Type IIb supernovae

摘要: I propose a scenario where the majority of progenitors type IIb supernovae (SNe IIb) lose most their hydrogen-rich envelope during grazing evolution (GEE). In GEE orbital radius binary system is about equal to giant star, and more compact companion accretes mass through an accretion disk. The disk assumed launch two opposite jets that efficiently remove gas from along orbit companion. efficient removal by prevents entering common evolution, at least for part time. might be continuous or intermittent. crudely estimate total time period in range hundreds years, GEE, up few tens thousands years intermittent GEE. key new point substantially increases volume stellar parameter space leads SNe IIb, both lower secondary masses closer separations.