The Delay Time Distribution of Type Ia Supernovae and the Single Degenerate Model

TL;DR

This paper presents a new theoretical delay time distribution for Type Ia supernovae based on single degenerate progenitor models, showing it aligns well with observations and supports the viability of the SD scenario.

Contribution

The study introduces a comprehensive SD model with two channels that produce a featureless power-law DTD consistent with observations, emphasizing the importance of winds and mass stripping.

Findings

The DTD follows an almost featureless power law ( ^{-1}) from 0.1 to 10 Gyr.

The SD model's wide companion mass range produces a DTD matching observations.

The SD scenario requires wind and mass-stripping processes for consistency.

Abstract

We present a theoretical delay time distribution (DTD) of Type Ia supernovae on the basis of our new evolutionary models of single degenerate (SD) progenitor systems. Our model DTD has almost a featureless power law shape (\propto t^{-n} with n \approx 1) for the delay time from t \sim 0.1 to 10 Gyr. This is in good agreement with the recent direct measurement of DTD. The observed featureless property of the DTD has been suggested to be favorable for the double degenerate (DD) scenario but not for the SD scenario. If the mass range of the companion star to the white dwarf (WD) were too narrow in the SD model, its DTD would be too limited around the companion's main-sequence lifetime to be consistent with the observed DTD. However, this is not the case in our SD model that consists of the two channels of WD + RG (red giant) and WD + MS (main-sequence star). In these channels, the companion stars have a mass range of \sim 0.9-3 M_\sun (WD+RG) and \sim 2- 6 M_\sun (WD+MS). The combined mass range is wide enough to yield the featureless DTD. We emphasize that the SD scenario should include two important processes: the optically thick winds from the mass-accreting WD and the mass-stripping from the companion star by the WD wind.