1. Classifying Stars Stars are classified by 3 Main Characteristics:
1. Size
2. Temperature
3. Brightness

2. Hottest (20,000-50,000*C) : (10,000*C) (6,000*C) (4,000-5,000*C)
Color reveals the temperature of a star.
Hottest (20,000-50,000*C)
: (10,000*C)
(6,000*C)
(4,000-5,000*C)
(3000*C)
Blue
White
Yellow
Red-Orange
Red

3. Brightness of Stars
Apparent Magnitude: Brightness as seen from earth
Absolute Magnitude: Brightness of a star from a standard distance

4. Hertzsprung-Russell Diagram
A graph plotting brightness and temperature.
90% of stars are
Main Sequence