ASTR& 101, Lab 6
Hertzsprung – Russell Diagram
You should have a plot of the H-R diagram from class using a spreadsheet program.
Print out your chart. Follow instructions below and turn in your written or typed responses along with
the chart.
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VII.
Mark the position of the Sun with a pencil.
Trace the Main Sequence with a highlighter.
What is special about the stars on the main sequence?
Corral the stars within the area you think is occupied by Red Giants by drawing a closed curve
around them using a pencil.
 Describe in detail why these are called Red Giants. Explain the “Red” and the “Giant” in
the name explicitly. Be sure to touch upon how it is that we can infer that these stars
have large radii.
Corral the stars within the area you think is occupied by White Dwarfs by drawing a closed curve
around them using a pencil.
 Describe in detail why these are called White Dwarfs. Explain the “White” and the
“Dwarf” in the name explicitly. Be sure to touch upon how it is that we can infer that
these stars have small radii.
What portion of the H-R diagram do most of the bright stars you plotted fall on? What does this
tell you about the intrinsic luminosity of these stars?
What portion of the H-R diagram do most of the nearby stars you plotted fall on? What does this
tell you about the intrinsic luminosity of these stars?
Describe one way in which use astronomers make use of the H-R diagram other than to classify
stars into different types.