Question

What characteristic of Cepheid variables makes them extremely useful to astronomers? A) Their absolute magnitude is related directly to their period of pulsation. B) Their absolute magnitude is directly related to their diameter. C) Their absolute magnitude is related directly to their metal content (heavy element abundance). D) Their absolute magnitude is related directly to their surface temperature.

Answer 1

Cepheid variables are extremely useful to astronomers because their absolute magnitude is related directly to their period of pulsation, enabling astronomers to measure their distance based on their period-luminosity relation.

Step-by-step explanation:

The characteristic of Cepheid variables that makes them extremely useful to astronomers is that their absolute magnitude is related directly to their period of pulsation. The longer the period of pulsation, the greater the luminosity of the star. This period-luminosity relation allows astronomers to measure the distance to Cepheid variables by observing their periods and comparing them to their known absolute magnitudes.

Answer 2

Cepheid variables are extremely useful to astronomers because their period of pulsation is directly related to their absolute magnitude. This period-luminosity relation allows astronomers to accurately measure the distance to cepheid variables by comparing their measured brightness to their known absolute brightness at a standard distance.

Step-by-step explanation:

Cepheid variables are extremely useful to astronomers because their period of pulsation is directly related to their absolute magnitude. The longer the period of a cepheid variable, the greater its luminosity. This period-luminosity relation allows astronomers to accurately measure the distance to cepheid variables by comparing their measured brightness to their known absolute brightness at a standard distance.