Type IIb supernova progenitors by fatal common envelope evolution

From stellar evolution simulations (using MESA) we conclude that the fatal common envelope evolution (CEE) channel for the formation of Type IIb core collapse supernova (SN IIb) progenitors can indeed account for some SNe IIb. In the fatal CEE channel for SNe IIb a low mass main sequence secondary star inspirals inside the giant envelope of the massive primary star and removes most of the giant envelope before it merges with the giant core. The key ingredient of the scenario studied here is that the tidally destroyed secondary star forms a new giant envelope. The mass-loss process in a wind during the evolution from the merger process until core collapse, i.e., until the explosion, leaves little hydrogen mass at explosion as inferred from observations of SNe IIb. In the case of a massive primary star with a zero age main sequence mass of M(ZAMS)=16Mo that during its giant phase swallows a main sequence star of mass M2=0.5Mo, we find at explosion a hydrogen mass of M(H)=0.02-0.09Mo, depending on the rotation we assume. We find similar values for M(ZAMS)=12Mo.