Download Slide 1 - Fort Bend ISD

Magnitude
• How bright a star looks depends on:
– How far it is from Earth
– How bright the star actually is
Apparent Magnitude
• Brightness as seen from Earth
• Closer objects can appear brighter than
objects far away
Absolute Magnitude
• Brightness a star would have if it were at a
standard distance from the Earth
• Scientists study globular clusters to compare
brightness of stars
• All about same distance
from Earth
Brightness of Stars
• Depends on size and temperature
• Betelgeuse fairly cool, but big. Shines brightly
• Rigel is a lot smaller than Betelgeuse, but it’s
hot, so it also shines brightly
Classifying Stars
• Classified according to
– Size
– Temperature
– Brightness (magnitude)
Color and Temperature of Stars
Betelgeuse
(red star)
Rigel
(blue-white star)
ORION
Color and Temperature of Stars
• Color reveals temperature of stars
• Red stars
– Cooler, about 3,200 degrees Celsius
• White stars
– About 5,500 degrees Celsius (the Sun)
• Blue stars
– Hottest stars, over 10,000 degrees Celsius
– Rigel is 15,000 degrees