Supergiant

Supergiants are among the most massive stars. They occupy the top region of the Hertzsprung–Russell 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 or Ia+.