Question

select the statement that accurately compares the luminosity (absolute brightness) of a main sequence white, class a star to a main sequence red, class m star. the sun would be brighter than both the white class a star and the red class m star. the red class m star would have a greater luminosity (absolute brightness) than the white class a star. the white class a star would have a greater luminosity (absolute brightness) than the red class m star. the luminosity (absolute brightness) of the stars would be equal because they are the same distance from earth.

Explanation:

On the Hertzsprung - Russell (H - R) diagram, which plots a star's luminosity against its temperature (or spectral class), main - sequence stars follow a pattern. Class A stars are hotter (and bluer/whiter) than class M stars. Hotter main - sequence stars (like class A) are more luminous than cooler main - sequence stars (like class M). The Sun is a G - type star. A - type stars are hotter and more luminous than the Sun, and M - type stars are cooler and less luminous than the Sun. Also, luminosity (absolute brightness) is an intrinsic property of a star and not related to its distance from Earth (that would be apparent brightness).

Answer:

The white class A star would have a greater luminosity (absolute brightness) than the red class M star.