- Dependence for the Evolution of Supernova Explosion Evolution of Supernova Explosion

The Supernovae Rates

We start with calculation of burst-like  star formation in a galaxy assuming all stars to have been formed simultaneously. Let G(t) be the SN rate in this galaxy after a time period t. Then for any kind of star formation rate history the rate of SN in the galaxy of age t will be

In order to obtain the SN rate, we approximate the SFR in the Universe by a combination of two functions - a -like SFR of the ``first generation'' stars (presumably ``elliptical galaxies''  with no subsequent star formation) and a constant SFR of the second generation (``spiral galaxies''  with a constant star formation):

Here T is the age of the Universe and is the average density of stars, is the fraction of elliptical galaxies. 

In the Scenario Machine code, we used supernovae types according to the following definitions:

• SN Ia(wd) - binary WD merging  event with .
• SN Ia(aic) - accretion induced collapse of a WD.   
• SN II - core collapse of a star with the initial mass (either single or binary with the initial orbital separation a>200 AU).
• SN Ib - the same as for SN II, but in a binary with a<200 AU. In such binaries, the hydrogen shell of the primary more massive star is in most cases removed due to tidal interaction between the components.

Computation of the evolutionary tracks of binaries enabled us to obtain the time evolution of the supernova rate of these 4 types as shown in Figure 51.

 

Figure 51: The evolution of the SN rate in a sample galaxy after an instantaneous star formation burst  (Jorgensen et al., 1996).