Origin of the Structure of the Kuiper Belt during a Dynamical Instability in the Orbits of Uranus and Neptune

Authors: Harold F. Levison, Alessandro Morbidelli (OCA), Christa Van Laerhoven, Rodney Gomes, Kleomenis Tsiganis

(Submitted on 4 Dec 2007)

Abstract: We explore the origin and orbital evolution of the Kuiper belt in the framework of a recent model of the dynamical evolution of the giant planets, sometimes known as the Nice model. This model is characterized by a short, but violent, instability phase, during which the planets were on large eccentricity orbits. One characteristic of this model is that the proto-planetary disk must have been truncated at roughly 30 to 35 AU so that Neptune would stop migrating at its currently observed location. As a result, the Kuiper belt would have initially been empty.

In this paper we present a new dynamical mechanism which can deliver objects from the region interior to ~35 AU to the Kuiper belt without excessive inclination excitation. Assuming that the last encounter with Uranus delivered Neptune onto a low-inclination orbit with a semi-major axis of ~27 AU and an eccentricity of ~0.3, and that subsequently Neptune's eccentricity damped in ~1 My, our simulations reproduce the main observed properties of the Kuiper belt at an unprecedented level.

Subjects: Astrophysics (astro-ph)

Cite as: arXiv:0712.0553v1 [astro-ph]

Submission history

From: Morbidelli Alessandro [view email] [via CCSD proxy]

[v1] Tue, 4 Dec 2007 15:34:43 GMT (789kb)

http://arxiv.org/abs/0712.0553

An Outer Planet Beyond Pluto and Origin of the Trans-Neptunian Belt Architecture

Authors: Patryk Sofia Lykawka, Tadashi Mukai

(Submitted on 13 Dec 2007)

Abstract: Trans-Neptunian objects (TNOs) are remnants of a collisionally and dynamically evolved planetesimal disk in the outer solar system. This complex structure, known as the trans-Neptunian belt (or Edgeworth-Kuiper belt), can reveal important clues about disk properties, planet formation, and other evolutionary processes. In contrast to the predictions of accretion theory, TNOs exhibit surprisingly large eccentricities, e, and inclinations, i, which can be grouped into distinct dynamical classes. Several models have addressed the origin and orbital evolution of TNOs, but none have reproduced detailed observations, e.g., all dynamical classes and peculiar objects, or provided insightful predictions.

Based on extensive simulations of planetesimal disks with the presence of the four giant planets and massive planetesimals, we propose that the orbital history of an outer planet with tenths of Earth's mass can explain the trans-Neptunian belt orbital structure. This massive body was likely scattered by one of the giant planets, which then stirred the primordial planetesimal disk to the levels observed at 40-50 AU and truncated it at about 48 AU before planet migration. The outer planet later acquired an inclined stable orbit (greater than 100 AU; 20-40 deg) because of a resonant interaction with Neptune (an r:1 or r:2 resonance possibly coupled with the Kozai mechanism), guaranteeing the stability of the trans-Neptunian belt.

Our model consistently reproduces the main features of each dynamical class with unprecedented detail; it also satisfies other constraints such as the current small total mass of the trans-Neptunian belt and Neptune's current orbit at 30.1 AU. We also provide observationally testable predictions.

Comments: 80 pages, 24 figures, 7 tables. Accepted for publication in The
Astronomical Journal

Subjects: Astrophysics (astro-ph)

Cite as: arXiv:0712.2198v1 [astro-ph]

Submission history

From: Patryk Sofia Lykawka [view email]

[v1] Thu, 13 Dec 2007 17:18:20 GMT (2795kb)

http://arxiv.org/abs/0712.2198