AQA GCSE Physics – Space Physics – The life cycle of a star

Watch this video which explains how different size stars are born, lives or die

Look at this chart and copy into your notes – it shows how stars the same size and stars much bigger than our sun life and die. This chart is taken from the AQA GCSE Specification

Read the following which gives more details of what happens at each stage.

The life cycle of a star depends on its mass, but in general, the process can be broken down into several stages:

Protostar: The first stage in a star’s life is the protostar stage, where a cloud of gas and dust collapses under its own gravity. As it collapses, it heats up, and nuclear fusion begins to occur at its core, creating light and heat.

Main Sequence: After the protostar stage, the star enters the main sequence stage, where it spends most of its life. In this stage, the star is in a state of equilibrium, where the energy it produces through nuclear fusion in its core is balanced by gravitational collapse. The star’s temperature, brightness, and colour depend on its mass.

Red Giant: Once the star has used up most of the hydrogen fuel in its core, it begins to expand and cool, becoming a red giant. During this stage, the star starts to fuse helium, which causes the outer layers of the star to expand and cool, turning red.

White Dwarf: After the red giant stage, the star’s outer layers are shed, leaving behind a hot, dense core known as a white dwarf. The white dwarf cools down and fades over time, becoming a black dwarf.

Supernova: For more massive stars, the end of their life cycle is a supernova. A supernova occurs when the core of the star runs out of fuel and collapses, causing a massive explosion that can outshine an entire galaxy. The explosion can create elements heavier than iron and can create a neutron star or black hole.

It’s important to note that the life cycle of a star can vary depending on its mass and can also be affected by other factors such as the presence of a companion star or the availability of fuel.

Copy the following notes into your notes

A star goes through a life cycle. The life cycle is determined by the size of the star

Fusion processes in stars produce all of the naturally occurring elements. Elements heavier than iron are produced in a supernova.

The explosion of a massive star (supernova) distributes the elements throughout the universe.

Make a slide show on the lifecycle of a star. There are prompts on the pdf below.

Watch this video which provides a nice summary of this section,

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