The hydrogen atoms in a star are also moving at high velocity because of the random motions caused by their high temperature. as a result, each atom is doppler shifted a little bit differently, leading to a finite width of each spectral line, such as the 656.46-nm line we were just discussing. for a star like our sun, this leads to a finite width of the spectral lines of roughly δλ=0.04nm. if our instruments can only resolve to this accuracy, what is the lowest speed v, greater than 0, that we can measure a star to be moving?