# Describe the life cycle of a star that is similar in mass to the Sun, beginning from a nebula and ending as a white dwarf.

> Cambridge International IGCSE Physics (0625) — 6.2 Stars and the Universe · Describe · 4 marks

## Mark scheme (4 marks)

1. A nebula (cloud of dust and gas containing hydrogen) collapses under gravity to form a protostar.
2. A stable star forms when the inward gravitational attraction is balanced by the outward gas pressure from nuclear fusion.
3. When the star runs out of hydrogen fuel, it expands to form a red giant.
4. The red giant contracts to form a planetary nebula, leaving a white dwarf at its centre.

## Key terms

- [nebula](https://www.gradenine.co.uk/glossary/nebula)
- [white dwarf](https://www.gradenine.co.uk/glossary/white-dwarf)

## Related

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Source: [GradeNine](https://www.gradenine.co.uk/q/describe-the-life-cycle-of-a-c87d5fdb) · Published by Druglandscape Ltd.