Stellar Evolution in Earth and Space Science Class

These flashcards cover key concepts related to stellar evolution, including the life cycle stages of stars, their end states, and the processes involved in their formation and death.

What is the process by which a star changes throughout its lifetime?

Stellar evolution.

What are the end states of low-to-medium mass stars?

They typically end as white dwarfs.

What occurs during the protostar stage?

A dense clump within a molecular cloud collapses under gravity, heating up as it contracts.

What marks the beginning of the main sequence stage in a star's life?

Hydrogen fusion begins when the core temperature reaches about 10 million Kelvin.

What happens to massive stars after they exhaust their hydrogen fuel?

They undergo a supernova explosion.

What are stellar nurseries?

Regions where new stars are born, formed from dense molecular regions.

What is formed as a result of stellar nucleosynthesis?

Elements heavier than beryllium.

What is a neutron star?

An extremely dense remnant formed from the core of massive stars after a supernova.

What is a black dwarf?

A theoretical end state of a white dwarf that has cooled and no longer emits heat.

What is the significance of a supernova explosion?

It spreads heavy elements necessary for forming new stars, planets, and life.

What happens to low-to-medium mass stars after their red giant phase?

They shed their outer layers and leave behind a dense core called a white dwarf.

What determines the path of stellar evolution?

The initial mass of the star.

What is the principle behind the formation of stars according to the star formation theory?

Stars form when gravity acts on particles in the expanding universe.

What are the three possible end states for high-mass stars?

They end as either a neutron star or a black hole.

What role does gravity play in the formation of a star from a nebula?

Gravity pulls the gas and dust together, leading to the formation of a protostar.

Why does a star shine?

Because of the energy released from nuclear fusion in its core.

What is a red giant?

A stage in a star's evolution where the core contracts and outer layers expand and cool.

During stellar evolution, what happens to the abundances of elements in a star?

The abundances change as the star evolves.

What is the life cycle sequence of a star?

Nebula → Protostar → Main Sequence → Red Giant → Supernova → White Dwarf/Neutron Star/Black Hole.