Largest Planet?

Tyche is the nickname given to a hypothesized gas giant planet located in the Solar System's Oort cloud. Astronomers John Matese and Daniel Whitmire of the University of Louisiana at Lafayette repeatedly claimed to have evidence of its existence based on irregularities among long-period comets. They noted that if Tyche exists, it should be detectable in the archive of data that was collected by NASA's Wide-field Infrared Survey Explorer (WISE) telescope. However, several astronomers have voiced skepticism of this object's existence.Analysis over the next couple of years will be needed to determine if WISE has actually detected such a world or not. 

A duo of planetary astronomers has grabbed media attention by claiming a planet four times the size of Jupiter may be lurking in the outer solar system. They call the planet Tyche. Many astronomers, however, say it probably isn't there. The claim by John Matese and Daniel Whitmire of the University of Lousiana-Lafayette is not new: They have been making a case for Tyche since 1999, suggesting that the giant planet's presence in a far-flung region of solar system called the Oort cloud would explain the unusual orbital paths of some comets that originate there.