Department of Homeland Security. The agencies slated to become part of the Department of Homeland Security will be housed in one of four major directorates: Border and Transportation Security, Emergency Preparedness and Response, Science and Technology, and Information Analysis and Infrastructure Protection.
On the H-R diagram, stars are not uniformly distributed. The  main-sequence stars appear in decreasing order, from hotter, more  massive blue stars to cooler, less massive râ¦ed stars. The stars nearest to Earth are not very bright, and thus appear at the bottom right of the H-R diagram, instead of the top of the diagram like the brightest stars.
The HR diagrams that we studied in Lesson 4 are very useful tools for studying stellar evolution. A typical HR Diagram (e.g., the one for the stars in the cluster M55, below) plots a single point per star to represent that star's color and luminosity (or brightness) as it is observed today. So, you can consider an HR Diagram of that type to represent a snapshot of a moment in the lifetimes of the stars plotted.