Research Paper On Brown Dwarfs

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.

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.

seen day and night in the sky. It is now known as the crab nebula, and is a breeding ground for smaller stars. Another way for a supernova to be created, is when a white dwarf siphons off hydrogen from another star to the point where it will become unstable and explode.

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

This would mean that the theory that dwarfs form similarly to stars despite being smaller and such holds true. If dwarfs had not emitted jets or done anything like this, it would mean that the dwarfs have a similar formation to that of planets.

Stars begin their life cycle as molecular clouds. Some event, such as a shockwave or collision of a galaxy, causes the cloud to collapse and form smaller pieces, which collapse inward on itself, and form a protostar. As the star collapses, gravitational energy creates heat, resulting in the rotation of the particles. During this phase of formation,

White dwarf formed, particularly when there is availability of multiple stars; from this multiple star, it can experience similar exciting end as a nova. The gravity of this star may drag the hydrogen from the external layer of star onto itself because of the closeness with the other.

After carbon sinks to the middle of the star it also fuses with itself and creates oxygen and now oxygen is at the center of the star. The same process repeats with oxygen and it forms iron. Iron is the last thing that is formed because it does not produce energy, therefore it will not fuse with itself, so it forms the core of the star. The elements in these layers have formed an onion. After iron is settled in the center, the star begins to cool and the star will start to compress. When the star compresses, the temperature begins to increase and eventually the star will explode resulting in a

Black holes are formed when massive stars collapse under the weight of their own gravity (Schoolworkhelper Editorial Team). The nuclear fusion in younger stars creates a constant outward pressure from the core (“Black Hole Images, Facts and Information”). This balances the pull from the gasses in orbit around the core, keeping the star stable (Schoolworkhelper Editorial Team). Once a star’s life is nearing the end, and its gasses have almost all been used up in the nuclear reactions, the star will collapse inward from the gravitational pull without the outward push of the reactions (Schoolworkhelper Editorial Team). This happens to stars of at least six to eight times the mass of our sun (Schoolworkhelper Editorial

There are many stages in the life-cycle of a star. Stars are formed in clouds of gas and dust, also referred to as a nebulae. The lifetime of a star depends on its size; if the star is massive, perhaps like the sun, it will have a shorter life-span. A star like a dwarf star, an extremely small star, will have a longer life-span. Stars begin as protostars, then go into main sequence stars, supergiants, and last but not least, the stars will become old and turn into either a white dwarf or a black hole. You may not be able to see every star in the night sky, but don’t be fooled, space is filled with gas and dust too thin to be seen by the naked eye; this gas and dust is called interstellar medium.

A white dwarf is what starts like the sun become after they have exhausted their nuclear fuel. A white dwarf can also be called a degenerate dwarf. White dwarf stars are very dense, its mass is compared to the sun while it’s volume is compared to the Earth. White dwarfs are one of the densest objects of matter.

A star’s life cycle is determined by mass; the larger a star is, the shorter its lifespan is. When stars are formed, they begin as clouds of gas and dust in nebulae. Because of gravity, the matter condenses into a sphere where hydrogen is combined with helium, forming a protostar. As energy is released through nuclear fusion, stars enter the main sequence, the longest phase of a star’s life where it reaches stable nuclear reactions.

These clumps are shaped into disks and, after approximately one million years, a protostar will form in its center. Protostars continue to run off the same gravitational energy that was released by the initial collapse and continue to suck in dusty material from the space around itself. Once protostars are hot and dense enough to burn Hydrogen and Helium in their core they enter the main sequence period of their lives (NASA). Now, we can classify these stars further based on their masses.

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.