Planet Nine Video Abstract Script

EVIDENCE FOR A DISTANT GIANT PLANET IN THE SOLAR SYSTEM
Konstantin Batygin and Michael E. Brown
Astronomical Journal 151,22, 2016 February

Continued observational characterization of a field of icy debris beyond Neptune, known as the Kuiper belt, is gradually unveiling a population of small bodies, whose orbital periods span thousands to tens of thousands of years. Remarkably, this aggregate of distant objects exhibits large-scale collective structure, that is strikingly puzzling within the framework of the present-day 8-planet solar system. Namely, the most distant orbits of the solar system occupy roughly the same plane, and have perihelia that are approximately co-linear. The clustering of the apsidal lines and of the orbital planes of the Kuiper belt objects cannot be explained by an observational bias and is highly statistically significant.  

What sculpts the intricate arrangement of the distant Kuiper belt? Numerical simulations reveal that an approximately 10 Earth mass planet, occupying an eccentric orbit with a period of 15,000-20,000 years, can naturally generate the observed confinement of long-period Kuiper belt orbits. This inferred member of our solar system, Planet Nine, likely resides in the same moderately inclined plane as the distant small bodies themselves. However, calculations reveal that its orbit must be anti-aligned with respect to those of the Kuiper belt objects. 

Unexpectedly, gravitational torques exerted onto the Kuiper belt by Planet Nine also generate a population of highly inclined, large semi-major axis Centaurs via the Kozai-Lidov effect. Continued analysis of both distant and highly inclined outer solar system objects provides the opportunity for testing the Planet Nine hypothesis, as well as further constraining the orbital elements and mass of the distant planet.