Key Concepts in Stellar Properties and Star Formation

Flashcards covering key vocabulary and concepts related to stellar properties and the processes of star formation.

Luminosity

The total amount of power (energy per second) that a star radiates into space.

Apparent brightness

The brightness of a star as seen from Earth, which depends on both the star's luminosity and its distance from Earth.

Stellar parallax

The apparent shift in position of a nearby object against a background of more distant objects, used to measure distances to stars.

Hertzsprung-Russell Diagram (H-R Diagram)

A graph that plots the luminosity of stars against their temperature, used to classify stars and to understand their evolutionary stages.

Main-sequence stars

Stars that are fusing hydrogen into helium in their cores, like our Sun, and occupy a specific position on the H-R diagram.

Binary star systems

Systems that consist of two stars orbiting around a common center of mass, which include visual binaries, spectroscopic binaries, and eclipsing binaries.

Variable stars

Stars that vary significantly in brightness over time, often due to changes in their equilibrium between power emerging from the core and power radiated from the surface.

Stellar nurseries

Regions in space where gas clouds form stars, known for their dark dusty appearance and the star formation processes occurring within them.

Brown dwarfs

Substellar objects that are not massive enough to sustain nuclear fusion in their cores, radiating primarily in infrared.

Helium fusion

The process by which helium nuclei combine to form heavier elements under high temperature and pressure, occurring in stars once core hydrogen is depleted.

Degeneracy pressure

A quantum mechanical effect that arises from the Pauli exclusion principle, preventing particles from occupying the same quantum state; it supports white dwarfs against gravitational collapse.

Supernova

An astronomical event that occurs during the later evolutionary stages of a massive star, resulting in a tremendous explosion that outshines an entire galaxy.

Planetary nebula

An astronomical object formed from the outer layers of a star that are expelled during the late stages of stellar evolution, leaving behind a white dwarf.

CNO cycle

A process of stellar nucleosynthesis in which hydrogen is converted into helium using carbon, nitrogen, and oxygen as catalysts in high-mass stars.

Stellar clusters

Groups of stars that are gravitationally bound to one another, useful for understanding stellar evolution and life cycles due to their shared age and composition.

Mass exchange

The process in binary systems where one star transfers material to its companion, usually occurring when one star evolves into a red giant.

Interstellar medium

The matter that exists in the space between stars, primarily composed of gas (mostly hydrogen) and dust.