Helium Synthesis

When stars died, chemicals other than hydrogen and helium formed, which led to the next level of complexity—Heavier Chemical Element. Most stars spent about 90% of their life over billions of years on during protons and hydrogen nuclei into helium nuclei. When they run out of fuel, the furnace at the center of the star stopped supporting the star, and gravity took over. Small stars did not have much pressure at the center. They burned hydrogen slowly over billions of years at relatively low temperatures. When they died, they would slowly fade away. However, great stars had so much mass that they can create enormous pressures and temperature, and when the giant stars ran out of hydrogen, the temperature got cranked up even higher, which led the star to collapse. The high temperature that the collapse caused was able to make helium nuclei fuse into nuclei of carbon. When a star used up its helium, it collapsed again, and the cycle started over. The star heated up and began to fuse carbon to form

Soon after the big bang the cosmic dust as well as gases combined and cooled off together to form stars. The nuclear fusion in stars converts hydrogen into helium and is a continuous process in the stars until hydrogen runs out at the core of the star. When hydrogen runs out, helium atoms fuse to form carbon atoms. Massive stars can synthesize heavier elements such as

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.

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

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

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

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

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

Helium makes up about Helium is the second most abundant element in the universe. It was discovered on the sun before it was found on earth. In 1868 a french astronomer, Pierre-Jules-Cesar Janssen noticed a yellow line in the sun’s spectrum while studying a total solar eclipse. With a wavelength of 587.49 nanometers Norman Lockyer realized that this line could not be produced by any element at the time. It was hypothesized that the sun was responsible for this mysterious yellow emission. Lockyer named the unknown element helium.

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)

The name comes from the Greek God of Sun – Helios. French astronomer Jules Jannsen first detected Helium during a solar eclipse in 1868. This substance detected was initially assumed to be sodium. Although these discoveries were occurred, the formal discovery of the element was made in 1895 by Scottish chemist, Sir William Ramsay.

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.