Unformatted text preview: P 2 = 4 π 2 a 3 G ( M 1 + M 2 ) Color and Spectral type reflect the temperature of star 2. Patterns Among Stars Herzsprung-Russell Diagram Plot of temperature vs Luminosity of stars Main sequence Plot mass vs luminosity --- lum is directly proportional to mass 4 Giants White Dwarfs Mass of star determines life time : big bright stars have short lives small dim stars have long lives Pulsating Variable Stars Cephied stars RR Lyrae Period of pulsation is directly proportional to luminosity – provides distances to galaxies 3. Star Clusters Two types of clusters: Open cluster Globular cluster...
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- Luminosity Apparent brightness, distance Luminosity Hipparchus