What are the main stages of stellar evolution?
The main stages of stellar evolution are: nebula (gas and dust cloud), protostar (collapsing under gravity), main-sequence (hydrogen fusion in core), red giant or supergiant (helium fusion and expansion), and finally, stellar remnants which could be a white dwarf, neutron star, or black hole, depending on the initial mass.
How do stars form and eventually die in the process of stellar evolution?
Stars form from collapsing clouds of gas and dust under gravity, eventually igniting nuclear fusion in their cores. They evolve through stages such as main sequence, red giant, or supergiant, depending on mass. Low-mass stars become white dwarfs, while massive stars may explode as supernovae, leaving neutron stars or black holes.
What factors determine the lifespan of a star during stellar evolution?
The lifespan of a star during stellar evolution is primarily determined by its initial mass and chemical composition. Higher mass stars burn through their nuclear fuel rapidly, leading to shorter lifespans, while lower mass stars burn fuel more slowly, resulting in longer lifespans. Stellar composition affects nuclear fusion rates and consequently the star's evolutive pace.
What role do mass and composition play in determining the path of stellar evolution?
Mass determines a star's lifetime, structure, and eventual fate, with high-mass stars evolving faster and ending as supernovae, while low-mass stars become white dwarfs. Composition, primarily hydrogen and helium, influences nuclear fusion rates and energy production, affecting a star's temperature, luminosity, and evolutionary track.
What is the significance of supernovae in stellar evolution?
Supernovae are significant in stellar evolution because they mark the end of a massive star’s life, dispersing heavy elements into space, which contribute to forming new stars and planets. They also trigger shockwaves, compressing gas clouds that can initiate star formation in nearby regions.