Suppose that a star is rotating at a speed of 50 km / sec at its equator. Its spectral lines wil

step 1 For this question we are looking at the Doppler shift of a certain hydrogen wavelength, a spectr

Suppose that a star is rotating at a speed of 50 km / sec at...

Suppose that a star is rotating at a speed of $50 \mathrm{km} / \mathrm{sec}$ at its equator. Its spectral lines will be spread out because one side of the star will be redshifted and the other side will be blueshifted. For the 656.3 -nm line of hydrogen, over how wide a range in wavelengths will the spectral line be spread?

Labs

Want to see this concept in action?

NEW

Explore this concept interactively to see how it behaves as you change inputs.

View Labs

Key Concepts

Rotational Broadening

Rotational broadening occurs when different parts of a rotating object, like a star, move at different velocities relative to the observer. This causes the spectral lines to widen, as one edge emits light that is redshifted and the opposite edge emits light that is blueshifted, leading to a spread in the observed wavelengths.

Wavelength Shift Calculation

The calculation of the wavelength shift uses the relationship ?? = (v/c)?, where v is the velocity of the source relative to the observer, c is the speed of light, and ? is the initial wavelength. This formula allows for quantifying the extent of the Doppler shift and, by extension, the broadening of spectral lines due to rotation.

Doppler Effect

The Doppler Effect is the change in the observed wavelength or frequency of a wave when there is relative motion between the source and the observer. In astrophysics, it explains why the light from moving objects, such as stars, appears shifted towards the red if moving away and towards the blue if moving closer.

Transcript

Please give Ace some feedback