Question

Which of the following statements is always true of two stars that have the same absolute magnitude?

1) They have the same temperature
2) They have the same luminosity
3) They have the same spectral class
4) They have the same surface area
5) None of the above

Answer 1

Two stars with the same absolute magnitude will have the same luminosity, which is a measure of their intrinsic brightness, regardless of other characteristics like temperature or spectral class.

Step-by-step explanation:

Two stars that have the same absolute magnitude will have the same luminosity because absolute magnitude is a measure of a star's intrinsic brightness. This is always true regardless of their temperature, spectral class, or surface area. It is important to note that luminosity is distinct from apparent brightness, which can vary depending on the distance from the observer to the star. Therefore, the correct answer to the question is that they have the same luminosity (answer 2). A star's absolute magnitude is a measure of its intrinsic brightness, while its luminosity measures the total amount of energy it emits per unit of time. Stars with the same absolute magnitude have the same luminosity, regardless of other factors such as temperature, spectral class, or surface area.