Status Report

The Wide-Binary Origin of The Pluto-Charon System

By SpaceRef Editor
July 22, 2020
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Mor Rozner, Evgeni Grishin, Hagai B. Perets

The Pluto-Charon binary system is the best-studied representative of the binary Kuiper-belt population. Its origins are vital to understanding the formation of other Kupier-belt objects (KBO) and binaries, and the evolution of the outer solar-system. The Pluto-Charon system is believed to form following a giant impact between two massive KBOs at relatively low velocities. However, the likelihood of a random direct collision between two of the most massive KBOs is low, and is further constrained by the requirement of a low-velocity collision, making this a potentially fine-tuned scenario. Here we expand our previous studies and suggest that the proto-Pluto-Charon system was formed as a highly inclined wide-binary, which was then driven through secular/quasi-secular evolution into a direct impact. Since wide-binaries are ubiquitous in the Kuiper-belt with many expected to be highly inclined, our scenario is expected to be robust. We use analytic tools and few-body simulations of the triple Sun-(proto-)Pluto-Charon system to show that a large parameter-space of initial conditions leads to such collisions. The velocity of such an impact is the escape velocity of a bound system, which naturally explains the low-velocity impact. The dynamical evolution and the origins of the Pluto-Charon system could therefore be traced to similar secular origins as those of other binaries and contact-binaries (e.g. Arrokoth), and suggest they play a key role in the evolution of KBOs.

Subjects: Earth and Planetary Astrophysics (astro-ph.EP)

Cite as: arXiv:2007.10335 [astro-ph.EP] (or arXiv:2007.10335v1 [astro-ph.EP] for this version)

Submission history

From: Mor Rozner 

[v1] Mon, 20 Jul 2020 18:00:00 UTC (2,010 KB)

SpaceRef staff editor.