Relation between proper motion and velocity components of an object. At emission, the object was at distance d from the Sun, and moved at angular rate μ radian/s, that is, μ = vt / d with vt = the component of velocity transverse to line of sight from the Sun. (The diagram illustrates an angle μ swept out in unit time at tangential velocity vt.)

Four runaway stars moving through regions of dense interstellar gas and creating bright bow waves and trailing tails of glowing gas. The stars in these NASA Hubble Space Telescope images are among 14 young runaway stars spotted by the Advanced Camera for Surveys between October 2005 and July 2006.

Positions and trajectories of 20 high-velocity stars as reconstructed from data acquired by Gaia, overlaid on top of an artistic view of the Milky Way

Runaway star speeding from 30 Doradus. Image taken by the Hubble Space Telescope.

UKIRT Hemisphere Survey image, showing the motion of CWISE J1249+362