Alpha Centauri A (G2V): B-V index 0.71 (yellow), confirming its placement in the yellow region of the Main Sequence. Sirius A (A1V): B-V index -0.03 (blue-white), fitting well in the hot, blue-white part of the Main Sequence. Procyon A (F5IV-V): B-V index 0.42 (yellow-white), correctly positioned at the Main Sequence transitioning to Sub-Giant. Sub-Giants (IV): These stars are located just above the Main Sequence. An example is: Procyon A (F5IV-V): Its transitional status is reflected by its placement just above the Main Sequence. Giants (III): Giants are situated above the Sub-Giants. An example is: Arcturus (K1.5III): B-V index 1.23 (orange), appropriately placed in the giant region, reflecting its spectral classification and color. Bright Giants (II): Bright Giants lie above the Giants. An example is: Canopus (F0II): B-V index 0.15 (white), confirming its location in the bright giant region. Less-luminous Supergiants (Ib): These stars are above the Bright Giants. An example is: Polaris (F7Ib): B-V index 0.60 (yellow), fitting well in the less-luminous supergiant category. Brightest Supergiants (Ia): The most luminous supergiants are at the top of the HR Diagram. An example is: Betelgeuse (M2Iab): B-V index 1.85 (red), correctly placed in the red supergiant region, reflecting its high luminosity and