published an article on Space.com, "Planet Nine Could Be Our Solar System's Missing 'Super Earth'," https://www.space.com/38431-new-evidence-planet-nine-existence.html
The hypothetical planet is believed to be about 10 times more massive than Earth and located in the dark, outer reaches of the solar system, approximately 20 times farther from the sun than Neptune is. While the mysterious world still has yet to be found, astronomers have discovered a number of strange features of our solar system that are best explained by the presence of a ninth planet, according to the NASA statement.
More at the link above.