BRAINCAKEEvolution of a Star
A star like the Sun passes through the following stages, each showing as a movement on the HR diagram.
1. Formation. A cloud of gas and dust (a nebula) collapses under gravity. Gravitational potential energy is transferred to thermal energy and a hot, dense protostar forms.
2. Main sequence. When the core is hot enough (about 107 K), hydrogen nuclei fuse into helium. Outward radiation and gas pressure balance the inward gravitational force, so the star is stable, in equilibrium. The Sun will stay on the main sequence for about 1010 years.
Sign in free to see the rest of this lesson, the R.E.C.I.P.E. recall steps and the quiz
BrainCake is free. Make an account in seconds and pick up where this page stops.
More in Astrophysics
- Wien's Displacement Law
- Stefan's Law
- Spectral Classes
- The Hertzsprung-Russell Diagram
- Supernovae, Neutron Stars and Black Holes
- The Schwarzschild Radius
- Type Ia Supernovae as Standard Candles
- The Doppler Effect and Red Shift
All 24 lessons in Astrophysics · All AQA A-level Physics topics