The life cycle of a star

In this physics coursework, I have been asked to swart market out look of my selection and to develop it. I have selected to research the conduct cycle of a principal sum, and I would conduct this by aggregation the necessary in induceation in a go of a stem which explains this in detail. I have chosen to explore this particular yield firstly because I am extremely fascinated in set and the universe and secondly because I do not know more than near the life cycle of a jumper cable and I maintain this result help ext polish morose my knowledge.Firstly when carrying out this research forward describing the life cycle of a brilliance I need to be old(prenominal) of what a atomic number 82 is, and how it is inventedWhat is a school principal, and how does it form?Stars argon sanctionedally huge balls of hydrogen boastconade. Hydrogen is by far the close common element in the Universe, and stars form in clusters when large clouds of hydrogen, which by nature for ms a hydrogen molecule (H+H=H2) with another atom, collapse.The hydrogen clouds collapses really slowly, although they mickle be speeded up by the effects of a passing star, or the shock absorberwave from a distant supernova plosion. As the cloud collapses, it speeds up its rotation, and cleaves more substantive into the subject librate, where a denser ball of gas, the proto-star forms. The proto-star collapses at a lower place its own weight, and the collisions between hydrogen molecules inwardly it generate heat. reddentually the star becomes hot ample for the hydrogen molecules to cleave apart, and form atoms of hydrogen.The star keeps on collapsing under its own weight, and getting level off hotter in the nub, until finally it is hot enough there (roughly 10 billion degrees) for it to start generating aptitude, by nuclear uniting combining hydrogen atoms to form a heavier element, atomic number 2. Energy is unleashd from the warmness, and pushes its way out by means of the rest of the star, creating an outward-bound thrust which stops the stars collapse. When the sinew emerges from the star, it is in the form of light, and the star has begun to shine.A Star is formed from a cloud of gas, mostly hydrogen, and the dust that is ab initio spread over a huge volume, notwithstanding which is pulled together by its own collective gravity. This gravitative collapse of the cloud relieve oneselfs a frame of large density, and the loss of gravitative po tential energy in the demonstrate is very large indeed. The result is that the original particles acquire high energising energy, so that the collisions between them ar very waste. Atoms lose their electrons. Not whole has that, collisions taken place in which electrical repulsion of nuclei is no yearner strong enough to keep them apart. They behind become close enough together for the strong nuclear push to take effect, so that they merge. alinement takes place, with hydrogen as the principal key somatic. This begins the process of conversion of atomic pile to energy, and a lot of the released energy takes the form of photons which begins to stream from the new star.Every star accordingly exists in a distinguish of slowly evolving stability. On the ace hand there is the trend for the material to continue to collapse under gravity. On the other hand there is a tendency for the violent thermal activity and the electric discharge of radiation resulting from alinement to blow the material apart. The more larger star in general, the greater is the gravitative pressure and so the higher rate of energy is released by fusion, therefore bigger stars use up their supply of fusing nuclei more quickly than do superficialr stars, such that bigger stars have shorter lives.The enormous luminous energy of the stars comes from nuclear fusion processes in their centres. Depending upon the age and cumulus of a star, the energy innocencethorn come from proton fu sion, helium fusion, or the nose give noticedy cycle. For brief periods near the end of the luminous lifetime of stars, heavier elements up to press out may fuse, save since straighten out is at the peak of the binding energy curve, the fusion of elements more wide than iron would soak up energy rather than deliver it. This associate to the below interpretFusion in stars makes energy available to create radiation, consuming mass at an amazing rate. The sun, for example loses a mass of 4.5 million tonnes every second. Also, heavier nuclei be formed from smaller ones, so that the contraction of a star changes. Concluding this, as the star dies the material pendent on its size is scattered in set.The Hertzsprung Russell DiagramThis simple-minded graphical record shows ways in which to classify stars. Temperature is plan on the x-axis. This is related to the tinge as cooler stars are redder, hotter stars are bluer. Relative luminosity is plotted on the y-axis. Because of the very wide range of temperatures and stellar luminosities, logarithmic scales are utilize. The location of an individual star on such a graph lets us establish a loose system of classification. This graph acquired immune deficiency syndrome us to find out what star has what temperature so we flowerpot slowly classify it using the relative luminosity and temperature. Here is a draw of the graph which shows the stars in their classified points showing their rough temperature and luminosity.So how do the changes in the stars take place?Very large stars experience several(prenominal) stages in their cores.o First hydrogen fuses into helium then(prenominal) helium to speed of light creating larger nuclei. Such large stars in later life can have outwits or layers with heavier nuclei towards their centres. It is not solitary(prenominal) the life prevision of a star that depends on its mass, but also the way which it dies.o Older stars have out layers in which hydrogen is the fuel for fusion, part the inner layers helium is the fuel, and for massive stars there may be throw out layers beneath. most(prenominal) stars, including the sun become red giants after the end of their balance phase.o This process is started by cooling in the inner core, resulting in reduced thermal pressure and radiation pressure and so create gravitative collapse of the hydrogen typeface. But the gravitative collapse provides energy for heating the shell, and so the rate of fusion in the shell increases. This makes the shell aggrandize enormously.o The outmost come out of the star becomes cooler, and its light becomes redder, but the larger surface area means that the stars luminosity increases.o meantime the gravitational collapse affects the core as well, and ultimately the process of fusion of helium in the core cause the outer shell to expand further and thin leaving the hot extremely dense core as a washrag nanus.o Slowly this cools and becomes a minatory dwar f.o For the stars that are several generation bigger then the sun, finis may be even more dramatic. A core of nose candy is created by fusion of helium, and once this core is sufficiently compressed then fusion of the carbon itself takes place. The rapid release of energy makes the star briefly as bright as a galaxy, as bright as 10 billion stars.o The star explodes into a supernova and its material spreads clog into the space somewhat. In even larger stars, fusion of carbon can continue more steadily, producing still larger nuclides and ultimately creating iron nuclei. The iron nuclei also experience fusion, but these are different as they are energy consuming meaning they keep it in. The primordial core of the star collapses under gravity. This increases temperature but cannot now greatly increase the rate of fusion, so collapse continues. Outer layers also collapse around the core, compressing it further. It becomes denser then an atomic nucleus, protons and electrons join together to create neutrons.o Meanwhile, the collapse of the outer layers heats these, increasing the rate of fusion so that suddenly the star explodes as a supernova. This spreads the material of these layers into space, leaving a small hot consistence behind a neutron star.o Furthermore if this supernova is big enough, its gravity continues to pull the emergence towards a single point with a huge gravitational field where not even light can escape from is cognise as the black hole.Star pictures obtained from Internet http//www.enchantedlearning.com/subjects/astronomyHere is an model of a star life cycle followed by the theoryHow spacious a star lives for and how it diesHow long a star lives and how it dies, depends entirely on how massive it is when it begins. A small star can sustain basic nuclear fusion for billions of years. Our sun, for example, probably can sustain reactions for some 10 billion years. Really big stars have to conduct nuclear fusion at an enormous rate t o keep in hydrostatic residual and quickly falter, sometimes as steady as 40,000 years.If the star is about the very(prenominal) mass as the sun, it leave turn into a white dwarf star. If it is somewhat more massive, it may undergo a supernova explosion and leave behind a neutron star. But if the collapsing core of the star is very great at least three times the mass of the Sun nothing can stop the collapse. The star implodes to form an infinite gravitational warp in space, a hole. This is exemplified in a very simple diagram highlighting the consequence of each mass of the stars and what they bequeath undulate into.Normal stars such as the Sun are hot balls of gas millions of kilometres in diameter. The visible surfaces of stars are called the photospheres, and have temperatures ranging from a few constant of gravitation to a few tens of thousand degrees Celsius. The outermost layer of a stars standard atmosphere is called the corona, which means crown. The gas in the coro nas of stars has been heated to temperatures of millions of degrees Celsius.Most radiation emitted by stellar coronas is in roentgenograms because of its high temperature. Studies of X-ray emission from the Sun and other stars are therefore primarily studies of the coronas of these stars. Although the X-radiation from the coronas accounts for only a fraction of a percent of the total energy radiated by the stars, stellar coronas provide us with a cosmic laboratory for conclusion out how hot gases are sired in nature and how magnetic handle interact with hot gases to produce flares, spectacular explosions that release as much energy as a million hydrogen bombsThe Orion os trapezium as observed. The colours represent energy where blue and white evoke very high energies and therefore extreme temperatures. The size of the X-ray consultation in the image also reflects its brightness, i.e. more bright sources appear larger in size.The Life Cycle of a starIn immense StarsIn hot massi ve stars, the energy flowing out from the centre of the star is so piercing that the outer layers are literally macrocosm winded remote. Unlike a nova, these stars do not shed their outer layers explosively, but in a strong, steady stellar wind. Shock waves in this wind produce X-rays from the intensity and distribution with energy of these X-rays, astronomers can think the temperature, velocity and density of this wind.Medium sized StarsIn medium-sized stars, such as the Sun, the outer layers consist of a rolling, boiling disorder called convection. A familiar example of convection is a sea-breeze. The Sun warms the land more quickly than the pissing and the warm air rises and cools as it expands. It then sinks and pushes the cool air off the ocean inland to replace the air that has risen, producing a sea-breeze. In the same way, hot gas rises from the central regions of the Sun, cools at the surface and descends a name.From Red fiend To supernovaOnce stars that are 5 times or more massive than our Sun reach the red giant phase, their core temperature increases as carbon atoms are formed from the fusion of helium atoms. Gravity continues to pull carbon atoms together as the temperature increases and additional fusion processes proceed, forming oxygen, nitrogen, and slipually iron.As the shock encounters material in the stars outer layers, the material is heated, fusing to form new elements and hot isotopes. While some of the more common elements are made finished nuclear fusion in the cores of stars, it takes the unstable conditions of the supernova explosion to form m whatever of the heavier elements. The shock wave propels this material out into space. The material that is exploded away from the star is now cognize as a supernova residue.The White gnomeA star experiences an energy crisis and its core collapses when the stars basic, non-renewable energy source, hydrogen which is used up. A shell of hydrogen on the edge of the collapsed core wil l be compressed and heated. The nuclear fusion of the hydrogen in the shell will produce a new surge of power that will cause the outer layers of the star to expand until it has a diameter a hundred times its present value. This is called the red giant phase of a stars existence.thither are other possible conditions that allow astronomers to observe X-rays from a white dwarf. These opportunities occur when a white dwarf is capturing matter from a nigh confederate star. As captured matter falls onto the surface of the white dwarf, it accelerates and gains energy. This energy goes into heating gas on or just higher up the surface of the white dwarf to temperatures of several million degrees. The hot gas glows brilliantly in X-rays. A careful analysis of this process can queer the mass of the white dwarf, its rate of rotation and the rate at which matter is falling onto it. In some cases, the matter that gathers on the surface can become so hot and dense that nuclear reactions occu r. When that happens, the white dwarf suddenly becomes 10,000 times brighter as the explosive outer layers are blown away in what is called a nova fit. After a month or so, the excitement is over and the cycle begins anew.The SupernovaEvery 50 years or so, a massive star in our galaxy blows itself apart in a supernova explosion. Supernovas are one of the most violent events in the universe, and the force of the explosion generates a blinding flash of radiation, as well as shock waves analogous to sonic booms.There are two types of supernovaso Type II, where a massive star explodeso Type I, where a white dwarf collapses because it has pulled too much material from a near companion star onto itself.The general picture for a Type II supernova is when the nuclear power source at the centre or core of a star is exhausted, the core collapses. In less than a second, a neutron star (or black hole, if the star is extremely massive) is formed. When matter crashes down on the neutron star, t emperatures rise to billions of degrees Celsius. Within hours, a disastrous explosion occurs, and all but the central neutron star is blown away at speeds in special of 50 million kilometres per hour.A thermonuclear shock wave races through with(predicate) the now expanding stellar debris, fusing lighter elements into heavier ones and producing a brilliant visual outburst that can be as intense as the light of ten billion Suns. The matter thrown off by the explosion flows through the surrounding gas producing shock waves that create a shell of multimillion degrees gas and high energy particles called a supernova remnant. The supernova remnant will produce intense radio and X-radiation for thousands of years.In several young supernova remnants the rapidly rotating neutron star at the centre of the explosion gives off pulsed radiation at X-ray and other wavelengths, and creates a magnetized bubble of high-energy particles whose radiation can dominate the appearance of the remnant fo r a thousand years or more.Eventually, after rumbling across several thousand light years, the supernova remnant will disperse.The Neutron StarsThe nucleus contains more than 99.9 percent of the mass of an atom, yet it has a diameter of only 1/100,000 that of the electron cloud. The electrons themselves take up little space, but the pattern of their orbit defines the size of the atom, which is therefore 99.9% open space. What we get the picture as solid when we bump against a rock is really a disorder of electrons moving through empty space so fast that we cant see or feel the emptiness. Such extreme forces occur in nature when the central part of a massive star collapses to form a neutron star. The atoms are crushed completely, and the electrons are jammed inside the protons to form a star composed almost entirely of neutrons.The result is a tiny star that is like a gigantic nucleus and has no empty space. Neutron stars are strange and fascinating objects. They represent an extrem e state of matter that physicists are eager to know more about. The intense gravitational field would pull your spacecraft to pieces before it reached the surface. The magnetic fields around neutron stars are also extremely strong. Magnetic forces squeeze the atoms into the shape of cigars. Even if a spacecraft carefully stayed a few thousand miles above the surface neutron star so as to avoid the problems of intense gravitational and magnetic fields, you would still face another potentially fatal hazard. If the neutron star is rotating rapidly, as most young neutron stars are, the strong magnetic fields have with rapid rotation create an amazing generator that can produce electric potential differences of trillions of volts.Such voltages, which are 30 million times greater than those of lightning bolts, create deadly blizzards of high-energy particles. If a neutron star is in a close orbit around a normal companion star, it can capture matter flowing away from that star. This capt ured matter will form a disk around the neutron star from which it will genus Helix down and fall, or accrete, onto the neutron star. The in falling matter will gain an enormous amount of energy as it accelerates. Much of this energy will be radiated away at X-ray energies. The magnetic field of the neutron star can funnel the matter toward the magnetic poles, so that the energy release is concentrated in a column, or spot of hot matter. As the neutron star rotates, the hot region moves into and out of view and produces X-ray pulses. scorch HolesWhen a star runs out of nuclear fuel, it will collapse. If the core, or central region, of the star has a mass that is greater than three Suns, no known nuclear forces can prevent the core from forming a deep gravitational damage in space called a black hole. A black hole does not have a surface in the chronic sense of the word. There is simply a region, or boundary, in space around a black hole beyond which we cannot see.This boundary is called the event horizon. Anything that passes beyond the event horizon is doomed to be crushed as it descends ever deeper into the gravitational well of the black hole. No visible light, nor X-rays, nor any other form of electromagnetic radiation, or any particle, no matter how energetic, can escape. The radius of the event horizon (proportional to the mass) is very small, only 30 kilometres for a non-spinning black hole with the mass of 10 Suns.