A supernova refers to several types of stellar explosions that create extremely bright objects composed of plasma, the brightness of which then decreases again by many orders of magnitude over the course of weeks or months. A supernova occurs in the case of a massive star that has depleted its fusion fuel and began shrinking under its own gravity, or a white dwarf that has accumulated material from its star guide, reached Chandrasekhar’s limit and undergone a thermonuclear explosion.
The explosion sets in motion a shock wave that propagates into space and forms supernova remnants and is accompanied by enormous temperatures, and under certain conditions, fusion reactions during the peak phase can produce some of the heaviest elements. Supernova explosions are the main source of all elements heavier than oxygen and the only source for many important elements. For example, all the calcium in our bones and all the iron in hemoglobin was synthesized in a supernova explosion billions of years ago.
Type I- They have no Balmer hydrogen lines.
Type Ia-Line Si II at 615.0 nm. Type Ia supernovae lack helium and contain a silicon absorption line in their spectrum near the peak of light.
Type Ib- Line He I at 587.6 nm. Type Ib supernovae are thought to be the result of the collapse of Wolf-Rayet stars.
Type Ic- Weak or no helium lines. There is some evidence that type Ic supernovae may be the cause of some types of gamma-ray bursts.
Type II- Has Balmer hydrogen lines. This type occurs after the fusion fuel has been depleted, the core has collapsed, and the energy of collapse has been transferred to the explosion.
Type II-P- Flat light curve. They have a large hydrogen envelope that captures the energy emitted in the form of gamma rays and slowly releases it.
Type II-L- Linear decrease of the light curve (dependence of magnitude on time). While type II-L, much smaller envelopes are expected to convert less gamma radiation into visible light.
There is speculation that some extra-large stars may instead form a “hypernova” before their extinction. These jets emit intense gamma rays and are among the few candidates to explain gamma-ray bursts.
SN 1006 – extremely bright supernova in the constellation Wolf
SN 1054 – the beginning of the formation of the Crab Nebula.
SN 1181 – supernova in Cassiopeia, its remnant is probably the star 3C 58.
SN 1572 – Supernova in Cassiopeia, observed by Tycho Brah.
SN 1604 – Supernova in Hadonos.
1885 – With Andromeda in the Andromeda Galaxy.
Supernova 1987A in the Large Magellanic Cloud.
Cassiopeia A – supernova in Cassiopeia.