Hertzsprung- Russell Diagram

H-R Diagram Compares the temperature, color and luminosity (brightness) of stars on a graph. The temperature is the surface temperature of the star The brightness of the star is its absolute magnitude

APPARENT MAGNITUDE VS. ABSOLUTE MAGNITUDE Apparent magnitude Absolute magnitude Measure of the amount of a star’s light received on Earth Measure of the amount of light a star actually gives off

STAR PROPERTIES Color indicates temperature Hot stars are Cool stars are YellowMedium temperature stars are Blue Red

White dwarfs small, hot stars leftover centers of old stars

Red-Giants When star runs out of energy, the center shrinks and the outer part expands outward. It will grow very large and cool.

Supergiants Very massive cool giant star

Main Sequence Stretches diagonal from the top left to the right bottom Our sun is an average main sequence star

Blue Supergiants Very massive blue stars Quickly use up energy and turn into Giants or Supergiants

Red Dwarfs Low-mass stars Oldest stars in galaxy

Putting it all together H-R Diagram AND Life Cycle