The Sun Is A Star

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The Sun is a star that is located at the centre of our solar system composed primarily of hydrogen and helium with smaller quantities of oxygen, carbon, neon, and iron. The sun keeps our planets in orbit due to its’ large gravitational forces and provides our planet with heat. There are many different ways in which stars can be classified, and The Sun is listed as a G-type Main Sequence star and is also known as a yellow dwarf. It is currently in a phase called the “main sequence” in which 4 hydrogen atoms are fused together to form 1 helium atom as well as energy (4.3x10-12 joules worth). Our sun is approximately half-way through its main sequence phase, and in approximately 5 billion years it will enter it’s post main sequence. Once all of the hydrogen in the core of the sun is depleted, the sun begins its post main sequence by ascending the red giant branch, starting with a phenomenon known as shell burning. Once the hydrogen core is depleted, outward radiation pressure stops and “inward gravitational attraction causes the helium core to contract, converting gravitational potential energy into thermal energy” (http://www.atnf.csiro.au/outreach/education/senior/astrophysics/stellarevolution_postmain.html). This thermal energy causes an increase in temperature which heats up the hydrogen shell surrounding its core, and once a certain temperature is reached, hydrogen fusion occurs which produces more energy than when it was on the main sequence. Due to this increase in
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