Stellar evolution

Definition

Stellar evolution is the process by which a star changes over the course of time. It encompasses the formation, life cycle, and eventual fate of stars.

5 Must Know Facts For Your Next Test

1. The initial mass of a star determines its entire evolutionary path and final fate.
2. Stars spend the majority of their lifetimes in the main sequence phase, where they fuse hydrogen into helium in their cores.
3. As stars exhaust their nuclear fuel, they evolve into red giants or supergiants depending on their initial mass.
4. Low to intermediate-mass stars end their lives as white dwarfs after shedding their outer layers to form planetary nebulae.
5. Massive stars undergo supernova explosions and may leave behind neutron stars or black holes.

Review Questions

• What factor primarily determines a star's evolutionary path?
• Describe what happens to low-mass stars after they leave the main sequence phase.
• What are possible end states for massive stars following a supernova?

Related terms

Main Sequence Star:

A stage in stellar evolution where a star fuses hydrogen into helium in its core.

Red Giant:

A late phase in stellar evolution where a star expands and cools after exhausting hydrogen in its core.

Supernova:

A powerful explosion that occurs when a massive star exhausts its nuclear fuel and collapses under gravity.