The Formation of the Stripped-envelope Type IIb Supernova Progenitors: Rotation, Metallicity, and Overshooting

Abstract

Abstract Type IIb supernovae (SNe) are believed to originate from core-collapse progenitors having kept only a very thin hydrogen envelope. We aim to explore how some physical factors, such as rotation, metallicity, overshooting, and the initial orbital period in binaries significantly affect the Roche lobe overflow and the formation of Type IIb SNe (also denoted SNe IIb). It is found that binaries are the main channel that are capable of producing Type IIb SNe progenitors in the mass range for initial masses below 20 M ⊙. The formation of Type IIb SNe progenitors is extremely sensitive to the initial orbital period. A less massive hydrogen envelope mass indicates a smaller radius and higher effective temperatures, and vice versa. Binary systems with initial periods between 300 and 720 days produce Type IIb progenitors that are a red supergiant. Those with an initial period between 50 and 300 days produce yellow supergiant progenitors, and those with initial periods shorter than 50 days blue supergiant progenitors. Both rapid rotation and larger overshooting can enlarge the carbon–oxygen core mass and lead to higher core temperature and lower central density at the precollapse phase. They are also beneficial to surface nitrogen enrichment but restrict the efficiency of the first dredge-up. SN IIb progenitors with low metallicity have smaller hydrogen envelope masses and radii than their high-metallicity counterparts. Ultrastripped binary models have systematically higher core mass fraction 12C left, which has an important influence on the compactness of Type IIb progenitors.