A new paper in The Astrophysical Journal Letters lays out new parameters for determining how Neptune’s orbit has changed over the millennia due to interactions with the nearby field of Kuiper Belt Objects (KBOs). Neptune was originally closer to our Sun but migrated out early on in our solar system’s history, and its resulting interactions with the KBOs likely scattered some into the inner solar system and caused the Late Heavy Bombardment that left the inner planets scarred with craters.
Now, this new research shows that Neptune’s eccentricity was not quite as non-existent as previously thought, meaning its orbit was far less circular at the time. It’s not a huge difference visually, but mathematically, it affected how the Kuiper Belt Objects ended up in their various orbits and inclinations, some more inclined than others. And as always, this information can be used to examine exoplanetary systems in their various ages to give us hints of what else and where else to look for more planets and smaller bodies.
A Highly Eccentric Journey (AAS Nova)
“Eccentric Early Migration of Neptune,” David Nesvorný, 2021 February 24, The Astrophysical Journal Letters