The Sun's absolute magnitude is about +5.The brightest stars in our sky have absolute magnitudes of about -10.What is the luminosity of these stars compared with that of the Sun,assuming that they have similar spectral light distributions?

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Quizplus · Accepted Answer

Absolute magnitude is a measure of the intrinsic brightness of a star, meaning its luminosity at a standard distance of 10 parsecs (32.6 light-years). The difference between the absolute magnitude of the Sun (+5) and that of the brightest stars in our sky (-10) is 15 magnitudes. Each magnitude corresponds to a factor of 2.5 in brightness, so the difference in brightness between the two is 2.5 to the power of 15, which is approximately 1 million. Therefore, the luminosity of these stars is about 1 million times greater than that of the Sun.

The Sun's Absolute Magnitude Is About +5