Long description

The figure illustrates a schematic H–R diagram indicating the locations of four regions where most stars are found. The horizontal axis has three ranges of information: (1) T in kelvin, (2) spectral type, and (3) colour index B minus V. The following points are marked on the horizontal axis, from left to right in logarithmic spacing at unequal distances. For T in kelvin: 40000, 30000, 20000, 10000, 5000, 3000, and 2000. For spectral type: O (about 30000), B (between 20000 and 10000), A (below 10000), F (between 7000 and 6000), G (about 5000), K (below 5000), M (above 3000), and L (above 2000). Colour index: negative 0.4 (between 40000 and 30000), 0 (at about 10000), and 1.5 (above 3000). The vertical axis is labelled M subscript V and ranges from 15 (at the bottom) to negative 10 (at the top) in decrements of 5 units, and L divided by L subscript solar and ranges from 10 raised to the negative fourth power (at the bottom) to 10 raised to the sixth power (at the top) in increments of 100 units. Diagonal parallel lines of constant stellar radius labelled 0.001 R subscript solar, 0.01 R subscript solar, 0.01 R subscript solar, 1 R subscript solar, and 10 R subscript solar from the vertical axis move toward the bottom right until the horizontal axis or the right vertical axis. The main-sequence region starts from the top left end and moves toward the bottom right end. The following stars are marked on the main sequence from the top to bottom: Zeta Puppis, Achernar, Regulus, Sirius A, Procyon A, Sun, 61 Cygni A, 61 Cygni B, Barnard’s Star, Proxima Centauri, and Wolf 359. The white dwarfs region is in the bottom left corner of the graph. Some of the white dwarfs are Sirius B (top left), Procyan B (bottom right), and Van Maanen 2 (bottom right of Procyan B). The red giants are on the top right. Some of the red giants (from bottom to top) are Pollux, Arcturus, and Aldebaran A. The supergiants region is at the top of the graph. Some of the supergiants are as follows: Rigel A (top left), Betelgeuse (top right), and Canopus (below and between Rigel A and Betelgeuse). The stars in the region between 10000 K and 7000 K are bluish-white. Moving to the right, the colours become white (around 5000 K), yellowish-white (between 5000 K and 3000 K), and orangey-white (between 3000 K and 2000 K).