I was wondering what would be the gravitational force caused by stars with high speed. As an example, I was trying to compute the gravitational force exerted by RX J0822-4300. This radio-quiet neutron star has a radial velocity of 1500Km/s (i.e. 0.5% c). The thing is that I am not quite sure which equations should be used in this problem. My guess would be to use General Relativity, since I need to bring relativity in the Universal Law of Gravity. Still, I don't know how should I proceed. Imagine that you are the observer outside the RX J0822-4300. P.S. This is not homework, just that I am wondering if this would be an application for General Relativity.