Which of the following four spectral luminosity classes would correspond to a red supergiant?
A) B7 I
B) G2 III
C) M3 V
D) M2 I

Question

Quizplus · Accepted Answer

A red supergiant would have a spectral class of M, which is matched by option D. The luminosity class I indicates a supergiant, whereas options A, B, and C have classes Ia (brighter than Ib) or III (less luminous than Ib, II, or Ia), which do not fit the characteristics of a red supergiant.

Which of the Following Four Spectral Luminosity Classes Would Correspond