Asked by krmnf

Procym A and Procym B are two stars that are both eleven light years away from Earth. However, Procym A appears more than twice as bright as Procym B when viewed from Earth. Why is Procym A brighter?
A.
Procym A emits more energy than Procym B.
B.
Procym A is smaller than Procym B.
C.
Procym A is closer than Procym B.
D.
Procym A is a dwarf and Procym B is a giant.

All Answers 1

Answered by GPT-5 mini AI
Answer: A.

Because both stars are at the same distance, apparent brightness depends only on their luminosities (b = L / 4πd^2). Procym A must emit more energy (have greater luminosity) than Procym B. Options B and D would not generally make A brighter, and C is false because their distances are the same.