Stellar Mid-Life and Old Age

These flashcards cover essential vocabulary and concepts related to stellar evolution, specifically focusing on life stages, fusion processes, and end-of-life outcomes for stars.

Stellar Mid-Life

The phase in a star's life cycle where it faces a balance between outward pressure and the inward pull of gravity.

Core Fusion

The process of nuclear fusion at the core of a star, which creates energy that counteracts gravitational collapse.

Luminosity

The total amount of energy radiated by a star per unit time.

Main Sequence Star

A stage in stellar evolution where stars spend most of their lives fusing hydrogen into helium.

Post-Main Sequence

The phase after a star exhausts hydrogen in its core, leading to changes in temperature and luminosity.

Triple-alpha Process

A set of nuclear fusion reactions by which helium is converted into carbon in the cores of stars.

Asymptotic-Giant Branch

A late phase in the life cycle of a star where helium fusion ceases and the star becomes a red supergiant.

Neutron Star

A compact star composed primarily of neutrons, formed from the remnants of massive stars after a supernova.

Supernova

An astronomical explosion that occurs at the end of a massive star's life cycle, resulting in the ejection of the outer layers.

Planetary Nebula

A shell of gas expelled from a star during the late stages of stellar evolution, leading to the formation of a white dwarf.

Iron Core

The final stage of nuclear reactions in massive stars, marking the end of fusion processes as it has no more nuclear energy.

Horizontal Branch

A phase in the stellar evolution when a star burns helium in its core after hydrogen fusion has ended.

Red Giant Branch

The region of the Hertzsprung-Russell diagram where stars expand and cool after exhausting hydrogen in their cores.

Chemical Composition of Star Clusters

The common elements and isotopes found in stars within the same cluster, indicating their similar formation history.

Shell Fusion

Nuclear fusion that occurs in a shell surrounding the stellar core, often after the core's fusion has ended.

Main-Sequence Life Span

The duration a star spends in the main-sequence phase, dependent on its mass and fuel consumption.