This image is a collaboration between Professor Robert Vanderbei and I. The image in the background and the HR diagram use the same data set. For more information about the HR diagram and the matlab code to create the diagram see the link below to Robert J. Vanderbei's website. He is a Professor, Operations Research and Financial Engineering Assoc. Faculty Member in Astro, Comp Sci, Math, MAE, PACM, SML, and BCF Fellow of AMS, INFORMS, and SIAM at Princeton University and a friend. 
https://vanderbei.princeton.edu/images/NJP/HRdiagMatlab.html