Module 04 – Measuring and Classifying Stars
The Hertzsprung-Russell diagram is an important tool in the classification of stars and the understanding
stellar evolution. The H-R diagram was discovered independently by two astronomers in early 20th
century using observations of star luminosity and surface temperature. With this lab exercise, you will
use Stellarium to collect stellar information and then form your own H-R diagram and see if you can find
how stars are group into different luminosity classes.
Background Question – Describe the four major groups of stars and where they are located on the H-R
diagram. The four major groups of stars are supergiants, giants, main sequence, and white dwarfs. White
dwarfs are located in the bottom left corner of the diagram, and the main sequence stretches in a curved
line from the top left corner to the bottom right corner of the diagram. The giant group is somewhat
small on the right side of the diagram, slightly above the main sequence area. Last, the supergiants are
at the top right corner of the diagram.
Object: Explain the purpose of this laboratory assignment in your own words. What do you think you will
accomplish or learn from this exercise? In my opinion, this assignment will help me to better understand
the classification/grouping of stars, and compare the luminosity between the stars closest to us and the
stars that are further away. Using Stellarium, I will be able to find out the absolute magnitude for some
of the stars and use that as a way of forming a H-R diagram to grasp the full concept of star groups.
Hypothesis: Write a simple hypothesis connected to different stars and the H-R diagram that you will be
able to test up the Stellarium software: The least amount of stars will be white dwarfs and most of the
stars will be in the main sequence area.
Procedure:
1) Open the Stellarium software. Open the Sky and Viewing options window (F4). Under the “Sky”
tab, uncheck the Atmosphere and Dynamic eye adaption.
2) Select the Landscape tab and uncheck “Show ground”.
3) For this lab, you will need to record the spectral class and absolute magnitude of a group of near
stars and a group of the brightest stars in the night sky. For each star, open the Search window