Low Mass Stars: Stellar Evolution

The star has been losing fuel and is burning out, so the star will begin to collapse. When collapsing part of the star will shoot into space and scientist believe this is how a supermassive black hole forms. When the hole is forming, dust and gas is collected from the galaxy surrounding the black hole. Light cannot be released because matter is squeezed together in a small space. Stellar black holes are small but dense and can have 20 times more mass than the sun. Mass is the property of a physical body. When a black hole is forming it is possible for mass to be pulled from stars around the whole. This will help the hole grow in power and

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

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.

Just like humans, everything in the universe has a purpose. From the beginning of the moment anything is created into existence it grows and fulfills its purpose. Stars are no different. Every day, stars are created by gravity which pulls the star together, the star builds up heat and pressure, and then fusion begins. The process in which a star goes through is known as a star's life cycle. All stars start at the basic nebula phase, change to a protostar, and go on to the main sequence star phase. After the main sequence star phase, there are two different divisions that are determined by the mass of the star. If a star is known as a low-mass star it will have different life changes than a high-mass star. A low-mass star will become a

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

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.

After the core of a star has depleted all its hydrogen in fusion, it undergoes its final stages of its life, or in other words, its death. The process path of a dying star depends on its mass. Low mass stars, from about 0.4 up to 8 solar masses will evolve from a planetary nebula to a white dwarf. Stars with larger the 8 solar masses will form supernovae, than either a neutron star for intermediate stars (8-25 solar masses) or a black hole for high mass stars (greater than 25 solar masses).

White dwarf is very small with diameter as the Earth and mass similar to the Sun formed when the core of red giant collapsed. The maximum mass a white dwarf can have is about 1.4 solar masses which is known as Chandrasekhar limit. A single star can be one mass at the start of life and still evolve into a white dwarf being 0.6 mass compressed into approximately the volume of the Earth. Even though it is hot, it is not as bright compared to its temperature of more than 8000° C. However, they cool down and fade over billions of years.

It is now a Red Giant after about 100 million years. The luminosity of the star has increased to around 100 Sols while still having a tiny core which is about a quarter of the mass of the star.

have greater gravity. To keep the star from collapsing, the star must fuse more hydrogen atoms to

It is a large bright star with a cool surface. Just like the Sun, it eventually runs out of hydrogen fuel at its center. Red Giants have a diameter of about 10 to 100 times the size of the Sun. The reason for why the Red Giants are so bright is because of its size, although there surface temperature is less hot than the Sun’s. If you were to measure the temperature, it would be about 2000 to 3000oC. Red Giants, very large stars, are also often called SuperGiants. These stars sometimes have diameter of up to 1000 times the size of the Sun, also having more than 1 000 000 times the luminosities of the Sun (Life cycle). These stars live for only a few thousand years to 1 billion years. Eventually the helium in the core runs out and fusion stops. The star shrinks until a new helium shell reaches the

Red giants are stars which are cooler, but more luminous than stars on the main trend — these are thought to be either dead stars or protostars.

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.

Stars go through tremendous things in the course of their life. In a star’s life they go through eight different phases. These phases can take many years to go through. When a star is made up it starts needing. Gas and dust in space to form what is called a nebula. Nebulae are the birthplace of stars. There are different types of nebulas one being an emission nebula. For example the Orion Nebula grows very brightly because of the gas that is in it which is energized by the stars that have formed inside of it (“Life of a Star”). Another type of nebula is a reflection nebula this is when starlight reflects off the greens of dust that are in a nebula. The last type of nebula is a dark nebula, these are very dense clouds of molecular hydrogen that can either partially or completely absorbed light from stars.