The Lifecycle of Stars and the Early Universe

VOCABULARY flashcards covering star formation from nebulae to planetary nebulae, including star classification by color and temperature, and key milestones in the early universe.

Nebula

Giant and massive clumps of scattered gas and dust particles where stars originate.

Protostar

The primal stage of a star's life where gravity causes dense regions in a nebula to spin, shrink, and form a flattened disk.

Main Sequence Star

A star born once the process of thermonuclear fusion of hydrogen to helium stabilizes, producing a tremendous amount of energy.

Red Giant Star

A stage where the star's core shrinks and heats while its outer atmosphere (mainly hydrogen) expands, causing it to grow larger, brighter, and cooler at the surface.

Planetary Nebula

An expanding shell formed when a star nearing exhaustion puffs out its outer layers into space during the final stages of its existence.

Blue Stars

The hottest category of stars, such as Rigel, which have a temperature of $25,000\,K$.

Blue-White Stars

A category of stars, including Sirius, with a recorded temperature of $10,000\,K$ according to the lecture notes.

Yellow Stars

Stars like the Sun that have a surface temperature of $6,000\,K$.

Orange Stars

Stars such as Aldebaran with a surface temperature of $4,000\,K$.

Red Stars

The coldest category of stars, with Antares listed as a primary example.

Hydrogen

The major natural fuel that stars fuse into helium at their centers or cores.

Big Bang Expansion

The event marking the beginning of the universe approximately $13.77$ billion years ago.

Afterglow Light Pattern

A developmental stage in the early universe occurring $375,000$ yrs. after the Big Bang.

1st Stars

Heavenly bodies that formed about $400$ million yrs. after the initial Big Bang expansion.

Betelgeuse

An example of a Red Giant star mentioned in the lecture notes.