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Beyond Our Solar System

Chapter 22

I. Properties of stars

A. Distance

1. Measuring a star’s distance can be very difficult

2. Stellar parallax

a. Used for measuring distance to a star

b. Apparent shift in a star’s position due to the orbital motion of Earth

c. Measured as an angle

d. Near stars have the largest parallax

e. Largest parallax is less than one second of arc

Light year – distance light travels in one earth year – about 9.5 trillion kilometer ( 5.8 trillion miles )

Stellar Brightness

Stellar Color and Temperature

Binary Stars and Stellar Mass

II. Hertzprung - Russell diagram

III. Variable Stars

IV. Interstellar Matter

V. Stellar Evolution

Star Birth

Protostar Stage

Main-Sequence Stage

Red Giant Stage

Burnout and Death

H – R Diagrams and Stellar Evolution

VI. Stellar Remnants

White Dwarfs

Neutron Stars

Black Holes

VII. The Milky Way Galaxy

Structure of the Milky Way Galaxy

VIII. Galaxies

Four Types of Galaxies

Galactic Clusters

IX. Red shifts

Expanding Universe

X. Big Bang Theory

A. Accounts for galaxies moving away from us

B. Universe was once confined to a " ball " that was

1. Supermassive

2. Dense

3. Hot

C. Big Bang marks the inception of the universe

1. Occurred about 20 billion years ago

2. All matter and space was created

D. Matter is moving outward

E. Outward expansion could stop if the concentration of matter is great enough

F. Gravitational contraction could perhaps happen 20 billion years in the future

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