Stars Life Cycle

Surprisingly, our sun isn't as big as it seems. There are many other stars that have more mass than our sun, and one example is the Rigel star. The Rigel star is a blue supergiant that is one of the brightest star found in the orion constellation. Its color is blue because it has 18 times the mass of the Sun, and is around 773 light years away from Earth/us. The Rigel star is also 117,000 times brighter than the sun. How did the Rigel star exactly form though? Well, it started as a protostar. Clouds of gas and dust mix and becomes dense, which attracts more and this begins to heat up. The cloud gets hot enough that it forms a newly born star, which lead us to the main sequence. Only 10 million years- which is young for a star, the Rigel had

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

Stellar evolution stars exist because of gravity. The two opposing forces in a star are gravity (contracts) and thermal nuclear energy (expands). Stage 1 Birth is where gravity contracts the cloud and the temperature rises, becoming a protostar. Protostars are a hypothetical cloud of dust and atoms in space which are believed to develop into a star. Astronomers are fairly certain of their existence. Protostars are formed about a million years after a gas clump from an interstellar gas cloud has started

The life cycle of a star is dependent on its mass. The larger the mass, the quicker it will die out, whereas stars which are no more than half the size of our Sun can live up to hundreds of billion years. However no matter how large the star is, they all begin their lives in a nursery known as a molecular cloud.

What happens to a star during the rest of its life depends of how massive

The life cycle of star is on an eternal cycle of birth, death and regeneration where the gases that form stars are ejected by the very stars when they die. This all starts with the helium gas and fusion of hydrogen. The life cycle of a star is formed from stellar nebula to high mass stars and low mass stars. Hertzsprung and Russell classified stars on the main sequence of the H-R diagram about 1910 that shows the relationship between luminosities and spectral types.

Stage 10 in the death of a star, you would start to think that with the core collapsing, that the star would just collapse and break apart. However, this only happens with starts under ¼ Sol and takes about a hundred billion years at the least. However, a star like our Sun, doesn’t die quite that quickly. Even under all the collapsing and expanding as a Red Giant, the core starts to burn helium in its core. Once this burning is about 100 million Kelvin and the density in the core has risen to the right level, the helium begins to fuse with carbon, which causes the reactor in the centre of the star to

The deaths of normal stars give birth to neutron stars. Neutron Stars are products of the so called supernova. Supernovae transpire during the death of a highly developed star which occurs when there is not enough nuclear fuel to keep the pressure intact inside the core of a star (Gursky 1975). The aftermath of a supernova is crucial because it frees iron, carbon, copper, and oxygen along with other elements found in a star. This explosion completely demolishes the star and has the ability to transform into either a black hole or neutron star (Freddy 2006). These supernovae are extremely bright and every 200 years there is an explosion that happens to be big enough and bright enough to be seen from earth. Neutron stars are very significant within the universe. It is said that the neutron star was discovered before the before the neutron. It was Lev Landau who first wrote about and studied dense stars. He focused his research on the idea there were objects in the universe that were denser than but as small as white dwarfs and regular stars (Haensel 2007). This focus leads to the discovery of the fascinating and complicated neutron star. The end is only the beginning for neutron stars.

This causes the ball, now a star, to shine. Depending on the mass of the star, they can reach different types of fusion. Normal stars that have a mass of up to 4 times the sun can only have hydrogen fusion, helium fusion, and carbon fission. Stars with a bigger mass is classified as a massive star, and they undergo multiple stages. They start out similar to the normal stars with hydrogen fusion, helium fusion and carbon fission, but continue over to oxygen fusion, and silicon fusion. The end product of Silicon is Iron. No star can fuse Iron, it will die. How much gas and dust is collected during the star’s formation determines the size and colour of the star. As time passes by, stars fight the inward pull of the force of gravity. The outward pressure created by the nuclear reactions pushing away from the star's core keeps the star whole. However, these nuclear reactions require hydrogen. Eventually the supply of hydrogen in the core runs out and the star begins to

After approximately 10 billion years after the star is considered to be a main sequence star, the hydrogen at the center of the core is depleted. This causes the nuclear fusion which had been previously fueling the star to die out. Helium replaces the hydrogen in the core, and the inner core begins to shrink due to gravity. This process speeds up once all the hydrogen is completely used up. The radius of the star has increased

it runs out of energy. Once the star dies, it may become a white dwarf, a neutron star, or a black

The process of a dying star is a more complicated and time-consuming procedure (it would take a few billion years). In fact, the dying process of a star that is similar to our Sun is slightly different from a star that is more massive than our Sun. For a star that is similar to our Sun, the process began with it shrinking as it cooled down after it ran of hydrogen, and eventually collapsed due to its weight. Once the core of a star began to contract, it would heat up, causing the outermost layer to expand. At this stage of the process, the star is now known as a red giant. Afterwards, the core would be so hot that it began fusing helium into carbon. Once the helium ran out, the core would expand then cool down. Again, the upper layers would expand and formed a planetary nebula. Finally, the core cooled down and became a white dwarf, which it eventually became a black

A star has 5 definite stages and 3 stages which can vary between stars. The 5 definite stages are a Nebula, a Star, a Red Giant, a White Dwarf and a Red Dwarf. The stages that can vary are a Supernova, a Neutron Star and a Black hole. As the star goes through each stage, it can change size dramastically. An example of this is a Red Giant, which is 100 time the size of the Sun, compared to a Red dwarf, only 1 tenth the size of the sun (Life cycle). An interesting fact is “The closest star to Earth is Proxima Centauri, located 4.2 light-years away. In other words, it takes light itself more than 4 years to complete the journey from Earth. If you tried to hitch a ride on the fastest spacecraft ever launched from Earth, it would still take you more than 70 000 years to get there from here.” (Interesting facts)

When we think of stars, we often think that they are all the same. We often think that they are all just big balls of gas burning up to billions of light years away. However, that isn't exactly true. The truth is that stars are very diverse. Just like anything else in our Universe, stars fall into many different classifications based on its defining characteristics. In this essay I will discuss several different types of stars.

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.