What are giant stars?
Giant stars are huge stars with a much larger radius and luminosity of the main sequential stars with a similar surface temperature. The main sequential stars have a mixed core, composed of hydrogen and helium. Giant stars have a core made of helium or even heavier elements such as carbon. This is because the giant stars began to exhaust the essential parts of their hydrogen fuel. Stars with 0.4 and 0.5 sun masses accumulate helium in their core as aged, and eventually accumulate pure helium core, but lack the pressure and temperature to the helium fuse. Hydrogen on the periphery of the core forms the shell of rapid fusion activity, because the massive core gravity compresses the hydrogen on it. The size of the star expands and becomes much more scattered. When the sun becomes a red giant for five billion years, its surface reaches the place where the Earth's orbit is today.
stars with larger than 0.5 sun mass can connect helium nuclei into oxygen and carbon through the triple alpha process. Although the nucleuso must reach 10
8 before the ignition, when this happens, produces the amount of energy, which increases the core size and reduces the pressure in the hydrogen building shell. This slows down the fusion reactions and contrainuitively reduces the size and temperature of the star. Thus, a massive star ends less light than less massive. Such stars are part of the so -called horizontal branch, because the graph of luminous intensity against the spectral type forms a horizontal line.
If there are fewer than 8 sunlight but larger than 0.5, the star builds the carbon in its core and begins to connect the helium on the shell outside the core. It becomes "asymptotic giant branch" or the star of AGB, as Helia fusion accelerates Aballoons his host star. These can create a supergiant and a hypergiant star.
In stars larger than 8 sunlights, the core is joined up to iron. When such a star creates an iron core greater than 1.44 solar materials, the core collapse begins. Mutually repulsive electron shells around iron jOádra repels each other under high pressure and temperature and begin to combine into another state of matter called neutronium, which are formed by neutrons that carefully stuck in the gigantic atomic core of the city size.
When the fusion reaction stops at the core, the star cannot produce sufficient energy to act against its own gravity and collapse. When the light elements fall inside, the almost uncomplicable neutron core is reflected. Bounceback is enough to send a star cloak exploding out into space at thousands of kilometers per hour. This event is called supernova and is how to create elements heavier than iron.>
The rest is what is called the rest of the stars or a neutron star. A teaspoon of his affairs weighs two million tons.