Gravitational Redshift for Wide Binaries in Gaia eDR3
  The Doppler effect is commonly used to infer the velocity difference between
stars based on the relative shifts in the rest-frame wavelengths of their
spectral features. In wide binaries, the difference in gravitational redshift
from the surfaces of the constituent stars with distinct compactness dominates
at separations above 0.01 pc. I suggest that this effect became apparent for
wide pairs in the Gaia eDR3 catalogue but incorrectly interpreted as a possible
modification of Newtonian gravity in the internal kinematics of very wide
binaries.
