Life Cycle Ofthe Stars

THE LIFE CYCLE OF THE STARS

The Life Cycle of the Stars

SCI 350

January 12, 2006

Abstract

Stars come in many definitions and in many forms today, there are Rock Stars, Movie Stars, There is even star shaped cereal for children but the most important stars we have our in our solar system. Lets look at the stars in the sky and space their origins of birth there attributes of life and there accolades in death.

The Life Cycle of the Stars

To discover the stars origin we look for its definition in Merriam Webster's Dictionary and we find almost an entire galaxy of definitions.

"Star

56 entries found for star. The first 2 are listed below.

Main Entry: 1star

Pronunciation: 'stÐ'r

Function: noun

Usage: often attributive

Etymology: Middle English sterre, from Old English steorra; akin to Old High German sterno star, Latin stella, Greek astEr, astronomer

1 a : a natural luminous body visible in the sky especially at night b : a self-luminous gaseous celestial body of great mass which produces energy by means of nuclear fusion reactions, whose shape is usually spheroidal, and whose size may be as small as the earth or larger than the earth's orbit

2 a (1) : a planet or a configuration of the planets that is held in astrology to influence one's destiny or fortune -- usually used in plural (2) : a waxing or waning fortune or fame b obsolete :"( Merriam Webster 2005)

Since there are actually 56 entries in the dictionary I choose the first two so as to key on a star of the solar system. Light is a very important part of a stars life because light, is what a star emits and makes it visible to us. Through the studying of starlight it was discovered that the Earth orbits the sun. also the aberration of starlight eventually lead to the discovery of stellar parallax in 1838.There are many forms of photons and electromagnetic waves and because of the various forms and shapes we are able to study star by the light that they emit.

In the Hierarchy of the universe stars play a very important role because they are believed to be huge bodies that have come into being from great clouds of light elements with the stars in them forming either simultaneously or in later evolution of the galaxies. (The Structure of the Universe 2005)

When a star is born out of enormous clods of gas and dust they come together into a sort of gigantic ball. Then there is the pressure from all of the gas and dust banging into one another and it can reach millions of degrees in temperature. The from this temperature come a life spawn out of an environment of nuclear fashion and it omits light and thus a star is born. The way that a star and our sun generate light is through the process of nuclear fusion, this has been discovered and proven through Einstein's theory of relativity E-mc squared and the makeup and chemical composition is very closely the same from star to star, although there are differences in each stars mass and what period of there life there are in at the time of study. There basically are three basic groups of stars which are

Low mass stars, and they are born with less than two ties the mass of our sun. Intermediate stars which are about 8 time the size and mass of our sun. Also there are high mass stars which are larger than 8 times the size ad solar mass of our sun. The formation of a star is made from a rain of matter which forms a protostellar disc very interestingly similar to the way our solar system was formed. The protostar is much like a star but its central temperature is not quite hot enough for fusion, once the temperature rises inside the photo star by gravitational contraction the temperature rises and the energy is carried to the surface and then when the core temperature reaches 10 million K it is hot enough to become a full fledged star.

Now that the star has become a fusion furnace of sorts it steadily burns hydrogen. The size and birth weights all vary and although it is not one hundred percent known why different clouds are of different mass it is known that there is a ten to one favor in the formation of low mass and intermediate mass stars over high mass stars. The Low mass stars spend there main life as a fusion machine which turns hydrogen into helium and a very slow and methodical pace. When the energy released by this fusion reaches the surface it is released into space and this is the star luminosity. Over a long, long time sometimes billions of years a low mass star consumes the hydrogen in its core and converts it to helium, at which point the core starts to contract and shrink. Once all of the hydrogen inside the stars core begins to become totally exhausted, the core pressure gives way to the crush of gravity because it has no more fusion occurring in its core at that time. As the core shrinks rapidly and the outer layers start to expand the stars shape begins to grow in size and its luminosity becomes extraordinary