BRAINCAKELife Cycle of a Star
What happens to a star after the main sequence depends mainly on its mass.
Main sequence. All stars spend most of their lives here, fusing hydrogen into helium in the core, with gravity balanced by outward pressure. More massive stars are hotter and more luminous, and use up their hydrogen much faster, so they have shorter main sequence lifetimes. The Sun will last about 1010 years; a star of 10 solar masses only about 107 years.
Low-mass stars (like the Sun):
• hydrogen in the core runs out, so the core contracts and heats up
• hydrogen fuses in a shell around the core and the outer layers expand and cool: the star becomes a red giant
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.
Key terms in this lesson
- red giant
- A cool, highly luminous, greatly expanded star formed when a low-mass star's core contracts and hydrogen fuses in a shell around it.
- planetary nebula
- The expanding shell of gas ejected by a low-mass star as it evolves from a red giant into a white dwarf.
- supernova
- A violent explosion marking the end of a high-mass star's life, briefly outshining a whole galaxy and scattering heavy elements into space.
- neutron star
- The extremely dense remnant of a supernova, made almost entirely of neutrons, left when a collapsing core is too massive to form a white dwarf.
- black hole
- A region of space where gravity is so strong that the escape velocity exceeds the speed of light, so nothing can escape.
More in Space
- The Inverse Square Law for Intensity
- Estimating Stellar Radius and Temperature
- The Hertzsprung-Russell Diagram
- Formation of a Star
- White Dwarfs, Neutron Stars and Black Holes
- Trigonometric Parallax
- Standard Candles
- The Doppler Effect and Red Shift
All 18 lessons in Space · All Edexcel A-level Physics topics