life cycle of stars Essay

Stars are the most recognized astronomical object in space and they represent the building blocks of galaxies. Stars distribute elements such as: carbon, nitrogen, and oxygen. A star develops from a cloud of hydrogen and helium, the dust clouds that are scattered throughout galaxies. An example of a dust cloud is the Orion Nebula. The gas and dust begin to collapse from its own gravitational pull. As the cloud collapses, the middle gets hotter. This is known as a prostar. A dense and hot core forms which begins to collect dust and gas. All this material may not end up as a part of the star but can become planets, asteroids, comets, or remain dust. A star about the size of our sun can up to 50 million years to mature. The smallest stars are

The super strong gravity of a black hole pulls gases off nearby stars with such a force that the gases give off x-rays as they form an accretion disk of matter that spirals into the black hole. (Gallant R ., 2000).

The sun is a star that is made up of hydrogen gas. The sun is unlike other stars that we see in the sky because the sun delivers energy and radiation that allows to living things to exist. Also, the sun is much closer than the other stars in the sky.

The life cycle of the Sun starts like all stars with a cloud of dust and gas made up of mostly hydrogen. If the cloud cools, it will shrink because of the gravitational pull between the particles

1. Why is the phrase “nursery of stars” an appropriate way of describing interstellar matter (nebulae)?

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.

Comparing red giants to the sun, they are about 1000 times larger. Compared to the sun’s temperature, a red giants temperature is about half as much. This is because the same amount of energy has to be spread out across a much more massive star causing it to be cooler than it was before. The name red giant was given to these stars because the change in temperature causes the star to shine in the redder part of the spectrum. Stars can spend anywhere between 1000 years and one billion years in the red giant phase. After a certain amount of time, the helium finally runs out and fusion stops. Since there is no more helium, gravity pushes the star inward. The stars outer atmosphere is then blown out into huge clouds of gas and dust which is known as planetary nebulae. These clouds of gas and dust are then made to make new stars. As for the core of the star, it is still there. The star is now a white dwarf. White dwarf stars occur when the red giant loses its outer atmosphere. White dwarf stars are extremely hot because they are composed of only the core of the star which is the hottest

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

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

Stars, such as our sun begin their life in an entirely different form from the one we come to recognize. Their lives begin in the bitter cold, around 10 degrees Kelvin, which is only a few degrees above the 3 degrees Kelvin temperature of the background of space itself. Their density is also extremely sparse, with a density of around 1 billion particles per cubic metre, which is only a wisp in comparison to the density of around 1410 kilograms per cubic metre that the sun like star will have during its time on the main sequence. Although they may be quite low in density, the clouds are absolutely enormous, spanning up to tens of parsecs (an astronomical unit of measurement that is determined to be around 19 trillion miles) across. In these clouds, there is an abundance of molecular and atomic gases of various types, which will serve as the rough material that will be used to create the stars and solar systems. Hydrogen is the most abundant element found within these clouds, although they can also contain many other trace elements of metals and gasses.

Stars generate energy via nuclear fusion of elements. Stars of the magnitude great enough to become type II supernovae possess the mass needed to fuse elements that have an atomic mass greater than hydrogen and helium. The energy generated by these fusion reactions is large enough that it is able to counter the force of gravity and prevent the star from collapsing, maintaining stellar equilibrium. The helium produced in the core builds

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

Stars change dramatically throughout their existence, due to the forces of gravity, in a process called stellar evolution. Stellar evolution describes how stars transform over time, from birth, through life which includes growth, and ending in death. This process can take billions of years, although the time scale depends on the mass of the star. Luminosity also plays a role in the evolution of a star.

When the star actually starts to run out of nuclear fuel some of the mass flows into the star's core. When the core becomes too heavy it cannot take its own gravitational force. Which causes the core to collapse, and as it collapses it results in a giant supernova. Many people worry that the sun will become into a supernova. That has no chance of happening because the sun does not have enough mass to become a supernova.

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.