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