How is a star's spectrum changed when looking at the absorption spectrum from an approaching star as compared to if the star were stationary?
A)All the absorption lines would shift, uniformly, toward the long wavelength end of the spectrum.
B)All the absorption lines would shift, uniformly, toward the short wavelength end of the spectrum.
C)All the absorption lines would shift toward the long wavelength end of the spectrum, each line shifting by an amount proportional to its wavelength.
D)All the absorption lines would shift toward the short wavelength end of the spectrum, each line shifting by an amount proportional to its wavelength.

Question

Quizplus · Accepted Answer

When looking at the absorption spectrum from an approaching star, the absorption lines will shift towards the short wavelength end of the spectrum due to the Doppler effect. This shift in wavelength is proportional to the velocity of the star, so each line will shift by an amount proportional to its wavelength. This is known as blueshift.

How Is a Star's Spectrum Changed When Looking at the Absorption