Yes, the ellipse of the orbit would change a bit, while still passing through the point where the impact happened. Most of the change would be on the opposite s

Yes, the ellipse of the orbit would change a bit, while still passing through the point where the impact happened. Most of the change would be on the opposite side of the ellipse. However, I think that for such a small velocity change, it is a reasonable approximation to assume that the ellipsis around the sun stays pretty much the same, and only the phase of the object (i.e. where it is on the ellipsis at which time) is affected.