Supernova classification

The entries in Table 11.1 can be traced back to observational results. The mass and size of the progenitor stars can be evaluated best from the bolometric light curves, i.e. the integrated energy radiated in the electromagnetic spec- 

For massive supernovae the absolute luminosity after about 120 days, together with the age of the supernova, gives a relatively accurate measure of the amount of 56Co synthesised in the explosion Hamuy et al. 2003B Elmhamdi et al. 2003. This measurement is now available for many core-collapse supernovae and is typically a factor 10 less than assumed in thermonuclear supernovae but spans almost a factor of 100 Pastorello et al. 2004. 

The long and rich light curve observed for SN 1987A is a clear demonstration of how the various physical effects form the light curve Leibundgut Suntzeff 2003. It shows many of the described features and some more. 

Hypernovae have been added to the list of supernovae and they represent the high energy end (at least in their kinematics) with the high velocities observed 

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Richard K. Clingempeel, Stellar classifications, http //oerlicon.freeyellow.eom/./ SuperNovae/Classifications.html... 

Supernova classification by observed properties. Different lines can be identified in the spectra. The assumed scenario causing the light burst is also given... 

When it became possible to obtain the spectrum of one of these objects in 1937, it was obvious that they looked like nothing yet known. All supernovas discovered in subsequent years displayed a remarkable uniformity, both in intensity and in behaviour. This observation led Zwicky to suggest that they might be used as standard candles to calibrate distance across the cosmos. But then, in 1940, a supernova with a completely different spectrum was discovered. It soon became clear that there were at least two classes of supernova, distinguished by their spectral features. It was the presence or absence of the Balmer lines of hydrogen near the maximum of the light curve that provided this classification. 

This article reviews the current understanding of the supernova explosions. After a brief historical introduction the two main classes of supemovae are described starting from the classification scheme currently employed. The different energy inputs for supemovae are presented. Despite their rather different energy sources supernovae from different types reach very similar luminosities. A notable exception to this are the Gamma-Ray Bursts, which are several orders of magnitude more energetic. The characteristics of each supernova type are presented. 

It was Walter Baade who made the connection between the historical supernovae and the observed emission nebulae at their positions, thus identifying the remnants of the explosions. The most prominent object is of course the Crab Nebular (Messier 1), the leftover from the supernova in 1054 Baade 1942 May all Oort 1942. With extensive observations of bright supernovae Minkowski Minkowski 1941 introduced two subclasses. Zwicky Zwicky 1965 refined the classification scheme for supemovae further. However, for several decades only two main classes were maintained until in the early eighties it became clear that at least one further subclass needs to be added. 

For the sake of presentation, we find still another classification useful. We will divide candidates for particle dark matter into three categories Type la, Type lb, and Type II (following a common practice in superconductors and supernovas). Type la candidates are those known to exist, foremost among... 

The analysis of nucleosynthesis in hypernovae suggests a possible classification scheme of supernova explosions [111]. In this scheme, core collapse in stars with initial main sequence masses Mms < 25 — 30M leads to the formation of neutron stars, while more massive stars end up with the formation of black holes. Whether or not the collapse of such massive stars is associated with powerful hypernovae ( Hypernova branch ) or faint supernovae ( Faint SN branch ) can depend on additional ( hidden ) physical parameters, such as the presupernova rotation, magnetic fields. [39], or the GRB progenitor being a massive binary system component [145, 117]. The need for other parameters determining the outcome of the core collapse also follows from the continuous distribution of C+O cores of massive stars before the collapse, as inferred from observations, and strong discontinuity between masses of compact remnants (the mass gap between neutron stars and black holes) [28]2. 

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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