Types of stars
- Main Sequence Stars: located along the main sequence of the H-R diagram, which expands from the upper left corner to the bottom right corner of the H-R diagram.
- Red Giant Stars: located at the upper right corner of the H-R diagram, red giant stars are very luminous but relatively cool.
- White Dwarfs: located at the lower left corner of the H-R diagram, white dwarfs are extremely hot, but not very big.
Cool stars radiate most of their energy in the red and infrared region of the electromagnetic spectrum and thus appear red, while hot stars emit mostly at blue and ultra-violet wavelengths, making them appear blue or white.