# HR Diagram of Star Clusters

In this exercise we will plot 3 HR diagrams of 3 star clusters. From the graphs we will be able to answer these three questions: (1) Rank the cluster from youngest to oldest, (2) Rank the cluster from closest to farthest, and (3) for each cluster, count/classify how many stars are main sequence, giant, and white dwarf. See below for the data to graph: Read the lab “lab-HRDiagram.pdf”. You can find this in our lab package under “Syllabus”. Basically you need to plot the HR-Diagram for three clusters and answers the three questions above. You can plotting these three clusters by hand using this graph: However plotting using Jupyter/Colab notebook will earn more credit. See Colab guidance below:

HR Diagram of Star Clusters

Next Watch Python Essential Training section and write a ~ 1 page review on sections 7 & 8 .

Finally answer this math question (2 points) : We observed the light from the start with wavelength λ’ = 656 nm. We know that in our lab this light has a wavelength of λo = 656.3 nm. Find the velocity of the star using the formula for Doppler shift of light in term of wavelength. See the formula in the link below