Explain why the temperature of star is related to the broadening of a spectral line from...

Explain why the temperature of star is related to the broadening of a spectral line from the star and if a broader spectral line indicates a cooler or hotter star.

Expert Solution

If the temperature of a star (or in general any object) is high, the average kinetic energy of the molecules in it is also large. Thus the molecules on average, possess higher velocities. This means that the relative velocity between any two molecules will high. Assuming that every molecule is radiating for the spectral line, due to the relative motion, the frequency of the signal received will be Doppler shifted by an amount which is characteristic of its velocity.

This range of frequencies due to the Doppler Shift will therefore broaden the Spectral Line. A broader spectral line thus indicates a hotter star.

genius_generous answered 2 years ago

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