Dead Astronomers and Planet X!

So, I decided to see if Carl Sagan ever said anything about Planet X and, of course, he did in his book Dark Star :

“Most of the stars in the sky are members of double or multiple star systems. In a typical binary system, two stars separated by several Astronomical Units are doing a stately gravitational fandango. Often the stars are more widely separated. In some instances we see two stars gravitationally bound to each other, but separated by 10,000A.U. At least 15 percent of the stars in the sky seem to have a companion star at this distance.

The nearest star system to the Sun- Alpha Centauri, 4.3 light-years away- is a double star with a third sun, a distant dim companion called Proxima Centauri, at 10,000A.U. from the two bright stars. Often the companion star is very faint, suggesting that there may be many still undiscovered widely separated binaries. It is possible that most of the stars in the Galaxy are so dim that astronomers call them brown or black dwarfs. Most distant companions might be of this sort.

The solar system seems to be an exception. We do not know of any companion to the Sun. But if we were not an exception, if the Sun had an invisible star in a very specific orbit, then the extinction clockwork again might be understood.”

I'm sure its just a coincidence...