The Birth and Death of Stars
Stars appear to us like shimmering diamonds in the night sky, however they are actually just gassy balls of heat which use atomic fusion to fuel themselves. Atomic fusion is the conversion of hydrogen to helium. Stars are made up of approximately 3/4 hydrogen and 1/4 helium. There are two types of stars; metal rich and metal poor stars. Metal rich stars live longer, such as our sun, which is around 4.5 billion years old.
There are many stages in a star's life cycle; from its formation as a nebula to its death as a white dwarf or neutron star. A nebula is a cloud of hydrogen gas which stars are formed from. An origin nebula glows brightly as stars are formed within it by the colliding of hydrogen and helium gasses and then slowly dies as stars break away. The surface temperature of a newly formed star can range from 2,000 degrees Celsius to 30,000 degrees Celsius. A red giant is a large, bright star with a cool surface. it is formed in the later stages of a star's life cycle as it slowly begins to run out of hydrogen gas. A red dwarf is a very small, cool star which burns very slowly and can live up to 100 billion years, although are very hard to pinpoint in the night sky as they are so small. A white dwarf is a very small, hot star in the final stages of its life cycle. They are shrunken remains of stars whose nuclear energy supplies have been used up. White dwarves have a very high density, for example, one spoonful has a mass of several tonnes which cool and diminish over billions of years. The last stage of a star is a supernova; the star's explosive death. There are two ways a supernova can occur. The first is when gas from one star collides with a white dwarf, causing it to explode and produce immense amounts of light and heat for a brief amount of time. The other way a supernova occurs is when stars ten times as big as our sun suffer internal nuclear reactions which leak out at the end of their life cycle and spark an explosion.
A Hertzprung -Russell diagram is used to describe the stages of a star, in particular, the spectral class, luminosity and magnitude. This allows scientists to compare stars and establish what stage a particular star is in and approximately how old it is. Scientists are able to use satellites to observe the brightness, colour and size of certain stars to identify what type they are. Astronomers can analyse the light given off by a particular star
A Hertzprung -Russell diagram is used to describe the stages of a star, in particular, the spectral class, luminosity and magnitude. This allows scientists to compare stars and establish what stage a particular star is in and approximately how old it is. Scientists are able to use satellites to observe the brightness, colour and size of certain stars to identify what type they are. Astronomers can analyse the light given off by a particular star