1. Stars

2. How do we classify Stars?
Star Properties
Color = _______________
Size = ________________
Number = _____________

3. Properties of Stars
Astronomers classify stars by their color, size, and brightness.
Other properties of stars are chemical composition and mass.

4. Color = Temperature – a stars color indicates the temperature of its’surface.
The hottest stars appear ______.
The cooler stars appear ______.
The spectrum of color in a star is from blues to greens to yellows and reds.

5. -----------------------
Size = Age
Think: What do you think happens to the size of stars as they get older?

6. Video: http://www. youtube. com/watch. v=PM9CQDlQI0A 1
Video: What did you learn about star size? 2. How does this clip relate to what else we have been learning?

7. Number = Amount of Brightness
The brightness of a star as viewed from Earth is dependent on many factors such as color intensity and distance.
Apparent Magnitude/Brightness:
the brightness of a star as it appears from Earth.
The apparent magnitude/brightness decreases as its distance from you increases
Absolute Magnitude/Brightness or Luminosity
how bright a star really is.
Which of these new words mean the same thing?

8. Hertzsprung-Russell Diagram (H-R Diagram)

9. Use your notes to compare/contrast these terms: 1. Magnitude: 2
Use your notes to compare/contrast these terms: 1. Magnitude: 2. Absolute Magnitude: 3. Apparent Magnitude: Size and Comparison of the Universe video: