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Doppler shift

(Doppler effect)
(wave frequency difference due to relative velocity difference with source)

A Doppler shift (or Doppler effect), in astronomy, is typically a change in electromagnetic radiation frequency and wavelength due to a radial velocity between the observer and the observed. It is a general property of waves, and is popularly known as the reason the sound of a passing vehicle has a higher tone as the vehicle approaches and lower when it has passed.

For EMR, the relationship between wavelength and relative velocity is:

δf = ——

Doppler shifts can also be caused by gravity, due to general relativity, offering another method of observation and analysis.


Referenced by:
binary star
dark matter
dark matter halo
velocity dispersion (σ)
double-line spectroscopic binary
extra-solar planet
frame of reference
Galactic All-sky Survey (GASS)
K correction
Kepler radius
kinematic distance
line shape function
mass function
moving-cluster method
OH/IR source
position-position-velocity space (PPV)
quenched galaxy
radial velocity (RV)
relativistic beaming
spectroscopic binary
stellar mass determination
stellar radius determination
stellar rotation
Tully-Fisher relation (TFR)
21cm line