Answer:
The Hertzsprung-Russell diagram plots stars according to their luminosity and temperature, which is also associated with spectral class.
Explanation:
The Hertzsprung-Russell is a diagram representing:
- The surface temperature of the stars on the x-axis
- The absolute luminosity of the stars on the y-axis
So, the H-R diagram shows the relationship between the luminosity (power output) of a star and its temperature.
Most of the stars in the diagram are located along a diagonal line going from the top left to the bottom right: the stars in this diagonal are the stars in the main sequence, which is the main phase of life of a star.
Also, the graph shows that for stars in the main sequence, as the temperature increases, the luminosity also increases: these are the blue supergiant stars located in the top left corner.
Then, apart from the main sequence line, there are other groups of stars located in the top right corner (red giants) and in the bottom left corner (red, white dwarfs).
So, the correct answer is
The Hertzsprung-Russell diagram plots stars according to their luminosity and temperature, which is also associated with spectral class.
