Question

hertzsprung - russell diagram
temperature (k)
40,000 20,000 10,000 7,500 5,500 4,500 3,000
luminosity (l$_{sun}$)
10$^{6}$
10$^{4}$
10$^{2}$
1
10$^{-2}$
10$^{-4}$
spectral class
o b a f g k m
based on this diagram, how do the characteristics of star 1 and star 2 compare?
star 1 is hotter and brighter than star 2.
star 1 is cooler and brighter than star 2.
star 1 is cooler and less bright than star 2.
star 1 is hotter and less bright than star 2.

Explanation:

Step1: Identify star - 1 and star - 2 on the diagram

Star 1 has a higher luminosity value (around $10^{4} L_{Sun}$) and a higher temperature (around 10,000 K) compared to Star 2. Star 2 has a lower luminosity (around $10^{-2} L_{Sun}$) and a lower temperature (around 5,500 K).

Step2: Analyze the temperature and luminosity relationship

On the Hertzsprung - Russell diagram, higher temperature corresponds to being "hotter" and higher luminosity corresponds to being "brighter". Since Star 1 has a higher temperature and higher luminosity than Star 2, Star 1 is hotter and brighter than Star 2.

Answer:

Star 1 is hotter and brighter than Star 2.