Can a huge device with a very high magnetic power disorient the course of an asteroid?

I am writing a story in which a red dwarf star coming closer to earth every 23 million years, disorients the trajectories of asteroids and comets in the Oort cloud. These comets and asteroids which impact earth causes m extinctions on earth. In my story, Ten thousand years ago, a Alien race who knew about this builds a huge device in our solar system. The device has a high magnetism capable of changing the trajectories of asteroids and comets with a earth impact course. The device can be anywhere in our solar system. Technology used can be very sophisticated. Thousands of years ahead of us. Can any one please tell me of a way to create this machine.