Question

1. why does polaris have a higher absolute brightness than sirius? 12. why does sirius have a higher apparent magnitude than polaris?

Explanation:

Question 11

Absolute brightness (luminosity) depends on a star’s actual energy output. Polaris is a Cepheid variable star, more massive and in a later evolutionary stage (e.g., supergiant), producing more energy (via nuclear fusion) than Sirius (a main - sequence star), so its absolute brightness is higher.

Apparent magnitude relates to how bright a star appears from Earth, depending on both luminosity and distance. Sirius is much closer to Earth (≈8.6 light - years) than Polaris (≈433 light - years). Even though Polaris has higher absolute brightness, Sirius’ proximity makes it appear brighter (higher apparent magnitude, as lower apparent magnitude numbers mean brighter, but here “higher apparent magnitude” in the question likely refers to a more positive (brighter - seeming) perception; actually, Sirius has a lower apparent magnitude number, but if we consider “higher” as more visually bright, its closeness overcomes Polaris’ higher luminosity in terms of apparent brightness from Earth).

Answer:

Polaris is more massive and in a later evolutionary stage (e.g., supergiant), producing more energy via nuclear fusion than Sirius (a main - sequence star), leading to higher absolute brightness.

Question 12