Why Are Peculiar Type Ia Supernovae More Likely to Show the Signature of a Single-degenerate Model?

Abstract

Although type Ia supernovae (SNe Ia) are very useful in many astrophysical fields, their exact progenitor nature is still unclear. A basic method to distinguish the different progenitor models is to search the signal from the single-degenerate (SD) model, e.g., the signal for the existence of a nondegenerate companion before or after supernova explosion. Observationally, some SNe Ia show such signals, while the others do not. Here, we propose a universal model to explain these observations based on the spin-up/spin-down model, in which a white dwarf (WD) will experience a spin-down phase before supernova explosion, and the spin-down timescale is determined by its initial mass, i.e., the more massive the initial WD, the shorter the spin-down timescale and then the more likely the SN Ia is to show the SD signature. Therefore, our model predicts that the SNe Ia from hybrid carbon–oxygen–neon WDs are more likely to show the SD signature observationally, as some peculiar SNe Ia showed.