Astronomy: Stellar Evolution, Distance Ladder, and Remnants

Vocabulary practice flashcards covering cosmic distance ladder methods, interstellar medium properties, stellar lifecycles, supernova mechanisms, and compact remnants.

Parallax

A triangulation method used to measure distances to nearby stars by observing their apparent shift in position at two different points in the year.

Cepheid Stars

Variable stars that follow a period-luminosity relation, fluctuating in true brightness and acting as standard candles to measure distances to nearby galaxies.

Spectroscopic Parallax

A method of calculating astronomical distance by placing a star on the H-R diagram to determine its luminosity and comparing that value to its apparent brightness.

Hertzsprung-Russell (H-R) Diagram

A scatter plot of stars showing the relationship between their luminosity and surface temperature or spectral classification ($O, B, A, F, G, K, M$).

Interstellar Medium

The matter and radiation that exist in the space between stars within a galaxy, consisting of molecular clouds and dust.

Molecular Clouds

Dense, cool regions of interstellar gas and dust shielded from radiation where gravity initiates star and planet formation.

Interstellar Dust

Microscopic particles that block visible light to create dark patches along the Milky Way, redden starlight, and are observable via infrared telescopes.

Skater Effect

The physical principle of conservation of angular momentum where a contracting or compressed celestial object spins progressively faster.

Helium Flash

The rapid onset of nuclear fusion in a red giant core that converts helium into carbon ($3\text{ }^4\text{He} \rightarrow 1\text{ }^{12}\text{C}$) as the core reaches temperatures around $10^{12}\,K$.

Planetary Nebula

An expanding outer shell of ionized gas puffed into space by an evolving low-mass star ($A, F, G, K, M$) at the end of its life.

White Dwarf

The compact, diamond-comprised core remnant left behind by a low-mass star with a mass below $1.4\,M$.

Type Ia Supernova

A supernova explosion following an implosion-bounce-explosion sequence that occurs when matter collapses to the point of leaving no empty space.

Type II Supernova

A high-mass stellar explosion that occurs when a massive star runs out of fuel after developing an iron core.

Chandrasekhar Limit

The mass thresholds governing stellar remnants: below $1.4\,M$ produces a white dwarf, between $1.4\,M$ and $3\,M$ produces a neutron star, and above $3\,M$ results in a black hole.

Neutron Star

A dense stellar remnant formed when high pressure forces protons and electrons to combine into neutrons and neutrinos, typical for stars between $1.4\,M$ and $3\,M$.

Pulsar

A rapidly rotating neutron star that sweeps beams of electromagnetic radiation across space like a lighthouse.

Black Hole

A region of spacetime with gravitational pull strong enough to trap everything, formed when a stellar remnant exceeds $3\,M$, when two neutron stars merge, or when a neutron star consumes a companion star.

Quasar

An actively feeding supermassive black hole that generates visible accretion disks emitting X-rays and enormous opposing relativistic jets.