Briefly explain the different types of supernovae

Question

What will be an ideal response?

Answer 1

In studying supernovae in other galaxies, astronomers have noticed that there are a number of different types. Type I supernovae have no hydrogen lines in their spectra, and astronomers have thought of at least two ways a supernova could occur without involving much hydrogen. Type II supernovae, in contrast, have spectra containing hydrogen lines and appear to be produced by the collapse and explosion of a massive star.A type Ia supernova is thought to occur when a white dwarf in a binary system receives enough mass to exceed the Chandrasekhar limit and collapse. The collapse of a white dwarf is different from the collapse of a massive star because the core of the white dwarf contains usable fuel. As the collapse begins, the temperature and density shoot up, and the carbon-oxygen core begins to fuse in violent nuclear reactions. In a few seconds, the carbon-oxygen interior is entirely consumed, and the outermost layers are blasted away in a violent explosion that, at its brightest, is about six times more luminous than a type II supernova. The white dwarf is entirely destroyed; no neutron star or black hole is left behind. This explains why no hydrogen lines are seen in the spectrum of a type Ia supernova explosion-white dwarfs contain very little hydrogen.The less common type Ib supernova is understood to occur when a massive star in a binary system loses its hydrogen-rich outer layers to its companion star. The remains of the massive star could develop an iron core and collapse, producing a supernova explosion that lacked hydrogen lines in its spectrum.