Luminosity class indicators use Roman numerals; which class indicates a supergiant?

Luminosity class indicators use Roman numerals; which class indicates a supergiant?

• A. V
• B. I
• C. II
• D. III

Answer: (B)

Luminosity class tells how large and luminous a star is for its temperature, and it's written with Roman numerals. The system goes I for supergiants, II for bright giants, III for giants, IV for subgiants, and V for main-sequence dwarfs. Supergiants are the largest and most luminous, so the designation I identifies them. The other classes describe smaller or less luminous stages, like main-sequence stars, giants, and bright giants. So the class that indicates a supergiant is the one labeled with I.

Luminosity class tells how large and luminous a star is for its temperature, and it's written with Roman numerals. The system goes I for supergiants, II for bright giants, III for giants, IV for subgiants, and V for main-sequence dwarfs. Supergiants are the largest and most luminous, so the designation I identifies them. The other classes describe smaller or less luminous stages, like main-sequence stars, giants, and bright giants. So the class that indicates a supergiant is the one labeled with I.