ASTR 1403 – Stars and Galaxies
The Nearest and the Brightest Stars Lab
Plot the stars from each list on the Hertzsprung–Russell diagram on the next page. Use the intrinsic brightness (absolute magnitude) on the y–axis and the temperature on the x–axis.
Note that the y–axis has negative magnitudes (the brightest stars) at the top and positive magnitudes (the dimmest stars) at the bottom. The x–axis is also “backward,” with hot stars on the left and cool stars on the right. Use a different color pen (or a pen and a pencil) for each group of stars to see how they differ.
What general trends do you see in the data in the plot? Draw a line following the main sequence defined by the nearest and the brightest stars together.
Draw a circle encompassing any white dwarf stars and a circle encompassing any giant or supergiant stars. List the giants and supergiants below. Also, list any white dwarf stars.
Giant or supergiant star
White dwarf star
Which star listed is the brightest intrinsically? Which is the intrinsically faintest?
Which star is furthest from the Sun? Why does it appear so bright in our sky?
Why does Alpha Centauri appear so bright in our sky?
How do the two groups of stars differ in the Hertzsprung–Russell diagram?
