Download Creating an HR Diagram

-7
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-1
0
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Alpha Centari
Sun
Bernard’s Star +
+
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Rigel
Deneb
Betelgeuse
Antares
Aldeberan
Vega
Pollux
Sirius
Procyon
Sun

Alpha Centari
+ +
Tau Ceti +
Sirius B
+
++
+
Bernard’s Star ++
++
+
++


25
20
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10
Procyon B
9
8
+
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3
2
Brightness (Magnitude) of Stars
• Apparent magnitude - a star’s brightness as
it appears from Earth.
– The lower the magnitude, the brighter the star.
– The higher the magnitude, the dimmer the star.
• 3 factors control a star’s apparent
magnitude.
– Size of the star
– Temperature of the star
– How far away the star is from Earth.
Brightness (Magnitude) of Stars
• Absolute magnitude - how bright a star
actually is from a standard distance of 32.6
light-years.
Absolute magnitude: +5.0
Apparent magnitude: -26.7
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Rigel
Deneb
Betelgeuse
Antares
Aldeberan
Vega
Pollux
Sirius
Procyon
Sun

Alpha Centari
+ +
Tau Ceti +
Sirius B
+
++
+
Bernard’s Star ++
++
+
++


25
20
15
10
Procyon B
9
8
+
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2