Probably the companion star lies within the invariable plane (the angular momentum plane of the solar system) inclined to the ecliptic by 1.5 degrees. This would provide the most stability for the planetary orbits.
There are good reasons why we do not see our dual star. It must be very faint in all ranges of electromagnetic emission and located in an area of the sky that “camouflages” it.
This basically rules out all types of stars except a black hole giving off only small amounts of radiation or a brown dwarf. The area toward the center of the galaxy is full of radiation, dust clouds, and background noise, making it difficult to track a faint object moving at an angular velocity of around 50 arcsec per year.
So we are predicting that our binary companion will be found in an elliptical patch centered around right ascension 17hr 45 minutes and declination –22 degrees.