Supemovae core collapse

Species are given with their proto-solar abundance by mass fraction, after Lodders (2003). The last column gives the yield calculated by Nomoto et al. for core-collapse supemovae within a Salpeter IMF between mass limits of 0.07 and 50 Mq. 

These parameters define an entirely unremarkable blue supergiant. Conventional wisdom had it that Supemovae of Type n occur either in red supeigiants, or perhaps, in the Wolf-Rayet phase of evolution. The central problem for the evolutionary models is therefore, how can the moment of core collapse be contrived to occur in a blue supergiant star There have already been many attempts made to address this question, and from these it is apparent that the main sequence mass must have been in the range 15-20 M . These models teach us that the end-point of evolution is... 

The term supernovae describes very different explosive processes in astronomy. There are essentially two object classes that provide an observable display that is rather similar. One is the core-collapse in a massive star where the freed gravitational energy is turned into radiation in many different ways. The rich variety of core-collapse supemovae is due to the many evolutionary chan-... 

The most abundant product of the evolution of massive stars is oxygen, in particular—the third most abundant isotope in the Universe and the most abundant metal. Massive stars are also the main source of most heavy elements up to atomic mass number A 80, of some of the rare proton-rich nuclei, and of the r-process nuclei from barium to uranium. In the following, we will briefly review the burning stages and nuclear processes that characterize the evolution of massive stars and the resulting core collapse supemovae. 

We have concentrated in this review on three broad categories of stellar and supernova nucleosynthesis sites (i) the mass range 1 M/M 10 of intermediate -mass stars, for which substantial element production occurs during the AGB phase of their evolution (ii) the mass range M lOM , corresponding to the massive star progenitors of type II ( core collapse ) supernovae and (hi) type la supemovae, which are understood to arise as a consequence of the evolution of intermediate mass stars in close binary systems. 

Here we focus on some recent highlights in both core collapse and thermonuclear supernova studies, which became possible mainly due to increasingly accurate radiation hydrodynamic calculations with a detailed treatment of neutrino processes. We also briefly describe recent success of asymmetric SN simulations (2D magneto-rotational collapse). Next we focus on recently established link between GRB explosions and energetic type Ibc supemovae (hypernovae) and discuss recent ideas on the GRB progenitors. We hypothesize that different core collapse outcomes may lead to the formation of different classes of GRBs. 

Core-collapse supemovae with kinetic energy of the ejecta 10 — 30 times as high as the standard 1 foe (lfoe = 1051 erg) are now collectively called hypemovae . The term was introduced by B. Paczynski shortly after the discovery of first GRB afterglows in 1997 by the Beppo-SAX satellite [114] based on qualitative analysis of possible evolutionary ways leading to cosmic GRB explosions. 

Figure 8 shows the different Li components for a model with ( Li/H)p = 1.23 X 10 . The linear slope produced by the model is independent of the input primordial value. The model of reference [60] includes in addition to primordial Li, lithium produced in Galactic cosmic-ray nucleosynthesis (primarily a + a fusion), and Li produced by the v-process during core collapse supemovae. As one can see, these processes are not sufficient to reproduce the population I abundance of Li, and additional production sources are needed. 

In discussing supemovae, one frequently encounters the terms Type la, Ib, and Ic and Type II supemovae. These are spectroscopic classifications. Type I supemovae do not have hydrogen in their spectra, while Type II do. The subclassification of Type I supemovae denotes whether they have silicon or helium in their spectra. Type la supemovae do not have hydrogen or helixim in their spectra but do have silicon. Type Ib supemovae do not have hydrogen or silicon in their spectra, but do have helium. Type Ic s show no hydrogen, helium, or silicon in their spectra. The connection to core-collapse or thermonuclear supemovae discussed above is that Type la supemovae are probably thermonuclear explosions of white dwarf stars. Type II supemovae are probably core-collapse explosions of massive stars. Type Ib and Ic supernova are probably also core-collapse explosions but of massive stars that have lost... 

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