Nuclear Fusion

After a time, the hydrogen runs out almost completely, and it collapses. New reactions begin to take place in the core and these reactions cause the star to expand rapidly. As the stars begin to deplete their new fuel, they switch to others. New elements are formed in the cores of stars but they become too heavy. The star has reached its end growth. When it reaches the end, a tremendous amount of energy is released and it begins to shed its outer layers, the gravity is too weak hold onto them anymore. Once the layers are removed, in the stars place is a fiery core called a planetary nebula. Eventually, the core runs out of fuel and it collapses. This star is now in a very dense state, and is called a white dwarf. Eventually, the white dwarf cools until it no longer shines. This dead star is called a brown dwarf.More massive stars, however, have more violent ways of dying. Some stars turn it into a supergiant. Supergiant stars are extremely bright, and are extremely large. Supergiant stars cores, can collapse violently and suddenly. This collapse causes a tremendous explosion, called a

The main idea for paragraphs 6-8 in When Stars Explode is how stars do explode. Here are some details: according to the text,“But these nuclear reactions do not make as much energy as hydrogen did. Within a few million years, the star has nothing left." The text also said “So the star's center collapses, scrunching itself into a small, dense object. Meanwhile, the star's outer layer shoots into space at millions of miles per hour. The star has exploded!"

After its core hydrogen is depleted, a red main sequence star will go supernova after its red giant phase.

As this slow contraction continues, the core temperature, density, and pressure of the star continues to increase. As the star shrinks it becomes so dense that it starts to compress helium. This results in the star to swell due to the hot core and leaving a relatively cool surface. Eventually the outer layers of the star expand outwards, increasing the size of the star. As the layers continue to expand, the surface temperature continues to cool, forming a relatively large star called a red giant.

Orion has two of the brightest stars, be Betelgeuse and Rigel. Betelgeuse is a red supergiant. The gravity of the star squeezes its core tightly, heating it to billions of degrees. It then fuses the helium to make heavier elements. When that happens, the star no longer produces energy in the core. Without the reactions in its core to push outward, gravity quickly causes the core to collapse, forming a neutron star.

The larger a star, the shorter their lifespan is, and they explode as supernovae, blasting out powerful shockwaves that create a chain-reaction that spews throughout the galaxy. Within just a few million years, the galaxy is forming stars up to hundreds of times more than a normal galaxy would. When all of the gas available is used up in about ten million years, the galaxy calms down and the period

Planetary nebula are formed in the outer core of the star that are vanished when the star of the Sun’s mass changes from a red giant to white dwarf. At this stage all the energy from the star fades away losing layers and forms a complex structure.

What is left after the huge explosion is another dwarf star, a neutron star, or the fierce black hole. A neutron star is about the size of a city like Los Angeles, but has the mass of about two suns. This means it is incredibly dense and has an unbelievable gravitational pull, almost 2 billion times that on earth. In fact, this pull is so strong that it bends radiation and allows astronomers to see the back of the star. They also spin up to 48 thousand times per minute due to the energy from the supernova.

Stage 8 is when the star starts to run out of fuel. It has spent close to 10 billion years burning hydrogen in its core and now it’s starting to run low and almost empty of the fuel it requires to keep burning. As the hydrogen starts to run low, helium levels start to increase in the higher temperature core as well as on the surface. However, the surface helium isn’t as noticeable because it doesn’t burn as high or fast as the inner core. But as the hydrogen completely runs out, the nuclear fusion subsides and a core of non-burning helium grows, forcing the burning of the star to head out of the inner core and up to the outer core. At this point, the radius of the star starts to grow rapidly because of the gas pressure and the core shrinks under the pressure of gravity.

evaporating due to the extreme radiation from the star. This is the first time something like this

known as the "binding energy". All stars have nuclear fusion occurring until the end of

If the fusion reactions in the core start becoming too few, the start can collapse change the composition of the sun and reactions that happen inside of the sun. If the inner reactions’ pressure becomes more than the outside pressure then the start will explode. The star will become white and become a nova. This balance helps regulate the star, like if the fusion reactions started to decrease then the star would shrink, increase heat and pressure, and increase the fusion reactions. Unlike all these variables of a star, our star is perfectly balanced, at this moment

When such a massive star consumes all its nuclear fuel, it undergoes a 'supernova' explosion and most of the matter is expelled. The extreme heat generated during such explosions can form elements heavier than iron through nuclear fusion.

To reach this final stage of existence all stars go through the same accepted pattern of evolution, except in the case for large mass stars who have much shorter lives due to burning their hydrogen fuel

Main sequence stars like our own sun enduring in a state of nuclear fusion during which they will produce energy for billions of years by replacing hydrogen to helium. Stars change over billions of years. When their main sequence phase ends they pass through other states of existence according to their size and other characteristics. The larger a star's mass, the shorter its lifespan is. As stars move toward the end of their lives, much of their hydrogen will be converted to helium. Helium sinks to the star's core and raises the star's temperature—causing its outer shell to expand. These large, puffy stars are known as Red Giants. The red giant phase is actually a prelude to a star shedding its outer layers and becoming a small, dense body called a White Dwarf. White dwarfs cool down for billions and billions of years, until they finally go dark and produce no energy at all. Once this happens, scientists have yet to observe, such stars become known as Black Dwarfs. A few stars avoid this evolutionary path and instead go out with a bang, exploding as Supernovae. These violent explosions leave behind a small core that will then turn into something called a Neutron Star or even, if the remainder is large enough, it is then turned into something called a Black Hole.