Stars and Galaxies Flashcards

Flashcards about Stars and Galaxies

Constellations

Groups of stars named over antiquity.

Ursa Major

A familiar constellation also known as the Great Bear.

Asterism

A pattern of stars that is not a constellation.

Big Dipper

A well-known asterism whose pairs of stars at the end of its bowl point to Polaris, the North Star.

Polaris

Another name for the North Star.

Star's Color

Indicates a star's temperature.

Red Star

A star that is cooler than a blue star.

Apparent Brightness

The brightness of a star as it appears to us.

Luminosity

The intrinsic brightness of a star, independent of how bright it appears.

LSun

Used to compare the luminosity of stars.

Hertzsprung-Russell Diagram

Graph of intrinsic brightness versus surface temperature for stars.

Average Stars

Stars that form a main sequence.

Exotic Stars

Stars that are above or below the main sequence.

Life cycle of stars

Begins as a nebula.

Protostar

Advances to this stage during star formation.

Star

Star when fusion in its core occurs.

Main Sequence

A star spends 90% of its life on this.

Red Giant

A star may become this and then burn out to leave a white dwarf behind.

Supernova

Stars may die in this kind of explosion leaving a neutron star or black hole behind.

White Dwarf

Cools for eons until it is too cold to emit light.

Nova

A nuclear blast on a white dwarf.

Core Collapse

Final stage of more massive stars is this, initiating an explosion called a supernova.

Fusion of hydrogen into helium

Powers all stars on the main sequence.

Proton-proton chain

Process by which hydrogen fuses into helium in lower-mass stars.

Black Hole

One of the things that might remain when a supergiant star’s core collapses into itself.

Black Hole

Gravitation at its surface is so intense that even light cannot escape.

Event Horizon

Boundary of a black hole.

Galaxy

Huge assemblage of stars, interstellar gas, and dust.

Milky Way

Most familiar galaxy.

Types of Galaxies

Three types of galaxies: elliptical, irregular, and spiral.

Active Galaxies

Galaxies that are emitting a huge amount of energy.

Starburst Galaxies, Galaxies with an active galactic nucleus

Two examples of active galaxies.

Starburst Galaxies

Galaxies that form stars at a very high rate.

Galaxies with an active galactic nucleus

Galaxies that have supermassive black holes in their centers.

AGN Jet

Jet from an active galactic nucleus.

Elliptical orbits

The motion of individual stars in a galaxy normally follow these.

Local Group

The Milky Way Galaxy and its neighboring galaxies.

Virgo and Eridanus clusters

Our local group is situated between these which make up our Local Supercluster.

Foam

Galaxies are arranged like this within which there are bubbles of super large voids.

Diurnal Motion

The apparent daily motion of stars due to Earth's rotation.

Blue Star

The color of stars that indicates the highest temperature.

Red Star

The color of stars that indicates the lowest temperature.

Lower Right

Location in the H-R diagram for a dying star that is cooling off.

Lower Left

Location in the H-R diagram for a dying star that has collapsed.

Thermonuclear reactions

The source of energy in the sun and stars.

Supergiant

The supergiant star that collapses to form a black hole.

Elliptical

Term that best describes the orbit of stars as they move within galaxies.

Starburst galaxies

The type of galaxy that is formed from violent disturbances such as collisions.

Local Supercluster

The local supercluster which contains the Milky Way .

Black hole

An object that is a spherical region of space surrounding an extremely dense collapsed object