The ion tail's direction — along the solar wind's velocity as the comet sees it: the wind's radial outflow minus the comet's own velocity. starToComet is a unit vector; velocityKmS the comet's heliocentric velocity.
starToComet
velocityKmS
The ion tail's direction — along the solar wind's velocity as the comet sees it: the wind's radial outflow minus the comet's own velocity.
starToCometis a unit vector;velocityKmSthe comet's heliocentric velocity.