The first thing that one notices is that there appear to be two hydrogen spectra shifted relative to each other owing to the motion of the stars relative to each other. Furthermore, one notices that the position of these lines will shift over time as the stars orbit around each other. Consider a binary star system that has bright lines at 656.72 and 656.86 nm. Over the course of six months the 656.72- nm line moves to longer wavelength and the 656.86-nm line moves to shorter wavelength, until finally the two have swapped (i.e., the spectrum of the star system again shows bright lines at 656.72 and 656.86 nm). Assume that the stars are of roughly equal mass and moving in a circular orbit with axis perpendicular to the line connecting the star system to the earth as shown in the figure (Figure 1). Review Constants Assuming that these spectral lines correspond to the 656.46-nm hydrogen line in the rest frame, estimate the speed V of the center of mass of the binary system. Express your answer in kilometers per second to three significant figures. View Available Hint(s) V = 151 km/s Submit Previous Answers Figure to Earth 1 of 1 Part B Correct Determine the mass M of each star. Express your answer in kilograms to one significant figure. View Available Hint(s) M = ? kg