Supergiants are among the most massive stars. In the Hertzsprung-Russell diagram they occupy the top region of the diagram. In the Yerkes spectral classification supergiants are class Ia (most luminous supergiants) or Ib (less luminous supergiants). They typically have bolometric absolute magnitudes between -5 and -12. The most luminous supergiants are often classified as hypergiants of class 0. Supergiants can have masses from 10 to 70 solar masses and brightness from 30,000 up to hundreds of… (More on Supergiant)