Galaxy Formation and Classification

These flashcards cover key vocabulary and concepts related to galaxy formation and classification from the provided lecture notes.

Pop I stars

Younger stars typically found in the disk of a galaxy, often containing heavier elements.

Pop II stars

Older stars found primarily in the halo and bulge of galaxies, usually with low metallicity.

Galaxy Formation

The process by which a galaxy forms, involving gas clouds contracting to form stars.

Star Life Cycle

The sequence of stages that a star undergoes from its formation to its death, including phases like red giant and white dwarf.

Supernova

A stellar explosion that occurs at the end of a star's life cycle, significantly enriching the surrounding gas with heavy elements.

Globular clusters

Tightly bound collections of older stars, often found in the halo of galaxies.

Edwin Hubble's Classification Scheme

A system used to categorize galaxies into elliptical, spiral, barred spiral, and S0 types based on their shapes.

Elliptical galaxies

Galaxies shaped like ellipses, containing older stars with little dust and no distinct disk structure.

S0 galaxies

Galaxies primarily composed of a bulge with a small disk, difficult to differentiate from elliptical galaxies.

Irregular galaxies

Galaxies that do not fit into the typical ellipticals or spiral categories, characterized by their young star population and gas-rich nature.

Barred spiral galaxies

Spiral galaxies that have a central bar structure composed of stars, distinguishing them from regular spirals.

Massive stars

Stars with much greater mass than our Sun, leading to different evolutionary paths including supernovae.

Stellar Nebula

A cloud of gas and dust in space where new stars are born.

Galaxy Disk

The flat, rotating region of a spiral galaxy where most of its young stars and gas are located.

Halo

The spherical outer region of a galaxy, populated with older stars and globular clusters.

Bulge

The central region of a galaxy, typically containing older stars and often surrounded by a disk.