Chapter 27: Stars and Galaxies

Flashcards for Chapter 27: Stars and Galaxies lecture.

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 stars point to Polaris.

Polaris

Also known as the North Star.

Star's Color

Indicates a star's temperature.

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

Unit used to compare the luminosity of stars.

Hertzsprung-Russell Diagram

Graph of intrinsic brightness versus surface temperature for stars.

Nebula

A star begins as this.

Protostar

A star advances to this stage after the nebula.

Star

A star becomes this when fusion in its core occurs.

Main Sequence

Stars spend 90% of their life in this stage.

Red Giant

A star may become this before turning into a white dwarf.

White Dwarf

Type of star left behind after a red giant burns out.

Supernova

Massive star death that leaves behind a neutron star or black hole.

Crab Nebula

Remnant of a supernova in the constellation Taurus.

Thermonuclear Reactions

The source of energy in the Sun and stars.

Main Sequence Stars

Fusion of hydrogen into helium releases energy and powers this.

Black Hole

Object with gravitation 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.

Elliptical, Irregular, Spiral

Three types of galaxies.

Active Galaxies

Galaxies that emit a huge amount of energy.

Starburst Galaxies

Galaxies that form stars at a very high rate.

Galaxies with AGN

Galaxies with supermassive black holes in their centers.

Elliptical orbits

Motion of individual stars in a galaxy.

Local Group

The Milky Way and its neighboring galaxies.

Virgo and Eridanus clusters

The Local Group is situated between these clusters.

Local Supercluster

Together, the Local Group, Virgo, and Eridanus clusters form this.

Cooler

A red star is this in temperature compared to a blue star.

The Sun

The monthly constellations change as Earth's path progresses around this.

Almost twice as hot as a red star

The temperature of Blue Star

Elliptical

Stars move in __ orbits around the center of the galaxy.

White dwarf

Dying star that has collapsed to a small size

Cephei A

Red hypergiant star within 3000 light-years of Earth

Betelgeuse A

Red supergiant star within 3000 light-years of Earth

Arcturus

Red giant star within 3000 light-years of Earth

Vega

Star within 3000 light-years of Earth

Sun

Average Star on the H-R Diagram

Sun and stars

Stars that are balls of plasma, much too hot for chemical reactions to occur.

red-hot

The longest wavelength is emitted by the star with the lowest frequency, the __ star.

pulls matter from its partner

This can lead to a nuclear blast for White dwarf.

collapse

Final stage of more massive stars is core __

huge assemblage of stars, interstellar gas, and dust

A galaxy is __

many orders of magnitude more

Active galaxies emit __ energy than our own Milky Way!

violent disturbances, such as the collision between two galaxies

Starburst galaxies result from

a foam

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