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Here is an HR Diagram of all 15 of the brightest stars in the sky visible in the United States, as well as other interesting stars. Star luminosities (plotted vertically) are given in terms of the sun, as are the lines of constant radius (slanted downward across the diagram). In case you are not seeing this in color, the blue stars are toward the left, followed by white, yellow, orange, and red on the right. Temperatures are given on the top scale, so hotter stars are to the left and cooler to the right. The bottom scales, list the spectral types, with ten implied subcategories. For example, an A5 star is about halfway between an A0 and F0 star. The dark curving line is the Main Sequence of stars, Giants refer to stars about 100 times as bright as the sun (rather than as large), and supergiants refer to those about 10,000 times as luminous. All the information you need to do this exercise can be found by reading this paragraph and the diagram itself. In every case, when the most "most" (or "least", etc.) is used, it means of the stars on the diagram which are numbered. Some stars are the right answer to more than one question.