Dark Photon

If we have a star, let us give an example of Alpha Centuri and a object orbiting it let us label OBJECT X. assume Object x is 1/2 light years away from alpha centuri. if ( and this will not happen, so this question has little purpose) alpha centuri is wiped out of existance, when will OBJECT X stop being influenced by its gravity? suddenly? or after half a year? can no message travel faster than light? and does this link in with the Graviton the assumed particle of gravity

If we have a star, let us give an example of Alpha Centuri and a object orbiting it let us label OBJECT X. assume Object x is 1/2 light years away from alpha centuri. if ( and this will not happen, so this question has little purpose) alpha centuri is wiped out of existance, when will OBJECT X stop being influenced by its gravity? suddenly? or after half a year? can no message travel faster than light? and does this link in with the Graviton the assumed particle of gravity