Fraunhofer lines are narrow absorption features in the solar spectrum caused by elements in the Sunβs atmosphere. Their precise laboratory wavelengths (rest wavelengths) are known, making them ideal references for measuring Doppler shifts.
When a star or galaxy moves toward or away from the observer, each spectral line is shifted in wavelength according to the lineβofβsight (radial) velocity. This is the classical Doppler effect, which for nonβrelativistic speeds is linear in the velocity.
By comparing the observed wavelength of a Fraunhofer line with its rest wavelength, astronomers can calculate the radial velocity of the source, providing crucial information about stellar motions, binary systems, and the expansion of the universe.
What are Fraunhofer lines?
How do I use this calculator to measure radial velocity?
What is the difference between non-relativistic and relativistic speeds in this context?
Can this calculator be used for galaxies as well as stars?
What is the significance of the Doppler shift in astronomy?
Results are for informational purposes only and do not constitute professional advice.
