-Refer to the figure.Polaris is a Type I Cepheid with a period of 4 days.What is its absolute magnitude?
A)+1
B)0.0
C)-1.0
D)-3.5

Name: -Refer to the figure.Polaris is a Type I Cepheid with a period of 4 days.What is its absolute magnitude? A)+1 B)0.0 C)-1.0 D)-3.5
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Question

-Refer to the figure.Polaris is a Type I Cepheid with a period of 4 days.What is its absolute magnitude?
A)+1 
B)0.0 
C)-1.0 
D)-3.5

Quizplus · Accepted Answer

The period-luminosity relation for Type I Cepheids is:$$M=-2.81\log P-1.43$$where M is the absolute magnitude and P is the period in days.For Polaris, P = 4 days, so:$$M=-2.81\log 4-1.43=-3.5$$

-Refer to the Figure