BRAINCAKEFormation of a Star
Stars form from interstellar clouds of dust and gas, mostly hydrogen. These clouds are called nebulae.
If a region of the cloud is dense enough, the gravitational attraction between its particles makes it begin to collapse. As the cloud collapses, gravitational potential energy is transferred to kinetic energy of the particles, so the temperature of the gas rises. The hot, dense, collapsing core is called a protostar. It glows because it is hot, but no fusion is happening yet.
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Key terms in this lesson
- radiation pressure
- The outward pressure exerted on matter by electromagnetic radiation escaping from a star, acting against the inward pull of gravity.
More in Astrophysics and Cosmology
- The Solar System and Galaxies
- Evolution of a Low-Mass Star
- Evolution of a Massive Star
- White Dwarfs and the Chandrasekhar Limit
- Neutron Stars and Black Holes
- The Hertzsprung-Russell Diagram
- Energy Levels in Atoms
- Emission and Absorption Line Spectra
All 24 lessons in Astrophysics and Cosmology · All OCR A-level Physics topics