NEMESIS/Hidden in Asteroid Belt? Mars Close Approach

A “four year orbit” around the Sun would not produce events at 4 year intervals for us. We would swing past it every year, plus or minus a bit, depending on whether it is pro or retrograde in its orbit.

A massive object in our orbital plane, and in the asteroid belt, would affect Mars and Ceres and the asteroids, and it would be noticed.

The barycenter of Jupiter and the Sun is sometimes above the surface of the Sun. Jupiter moves the entire solar system, including the Sun. A star in our orbital plane, and that close, would be noticed.

A brown dwarf in the asteroid belt would be very visible, from its own luminosity and from reflected sunlight.

The video is all wrong.