No Planet X

The third closest star system to the sun, called WISE J104915.57-531906, is at the center of the larger image, which was taken by NASA's Wide-field Infrared Survey Explorer (WISE). It appeared to be a single object, but a sharper image from Gemini Observatory in Chile (inset), revealed that it was binary star system, consisting of a pair of brown dwarfs. This is the closest star system to be discovered in nearly a century. The discovery was announced in March, 2013. Caption and Image: NASA/JPL/Gemini Observatory/AURA/NSF/Berkeley.edu

The third closest star system to the sun, called WISE J104915.57-531906, is at the center of the larger image, which was taken by NASA’s Wide-field Infrared Survey Explorer (WISE). It appeared to be a single object, but a sharper image from Gemini Observatory in Chile (inset), revealed that it was binary star system, consisting of a pair of brown dwarfs. This is the closest star system to be discovered in nearly a century. The discovery was announced in March, 2013.
Caption and Image: NASA/JPL/Gemini Observatory/AURA/NSF/Berkeley.edu

There seems to be no Planet X. There has been an ongoing idea of a planet outside the orbit of Pluto. Surveys by the Wide-Field Infrared Survey Explorer (WISE) turned up thousands of “new to us” stars and brown dwarfs within 500 light-years, but no Planets.

The outer solar system probably does not contain a large gas giant planet, or a small, companion star

– Kevin Luhman of the Center for Exoplanets and Habitable Worlds at Penn State University, University Park, Pa., author of a paper in the Astrophysical Journal describing the results.

The recent study, looking at WISE data found no objects Saturn sized or larger to a distance of 10,000 A.U. and no Jupiter sized or larger out to 26,000 A.U. In rough terms 1 A.U. is about 150 million km / 93 million miles.

Read more about this at The WISE page at Berkeley, it is worth the visit I promise!.