A star is moving toward the earth at 250 km/s. What can you say about the wavelength of the h-alpha absorption line that you wou

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2 years ago

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ld detect in the star's spectrum?

1 answer:

Juli2301 [7.4K] · Answer 1 · 2023-08-14T19:41:46+03:00

The wavelength of the h-alpha absorption line that you would detect in the star's spectrum will be 54.67 * $10^{-2}$ nm

If the object is moving towards or away from us with some radial velocity, shifts can be observed in the location of the absorption

since, material is moving towards us a shift to shorter wavelength will be observed

shift = rest wavelength * ( radial velocity / speed of light )

= 656 * $10^{-9}$ * (250 * $10^{3}$ / 3 * $10^{8}$ )

= 54.67 * $10^{-2}$ nm

The wavelength of the h-alpha absorption line that you would detect in the star's spectrum will be 54.67 * $10^{-2}$ nm

learn more about radial velocity:

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