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The Dwarf Planet Ceres revealed the presence of ammonia and other unique properties compared to other asteroids in the main belt which suggests that it was not formed in situ. We model the early dynamical evolution of the outer Solar System to study possible dynamical mechanisms to implant a Ceres-sized planetesimal in the asteroid belt from the trans-Saturnian region. We calculate that the fraction of the population of Ceres-sized planetesimals that are captured in the asteroid belt is in the range of 2.8e-5 to 1.2e-3 depending on the initial location in the outer planetesimal disk. The captured bodies have a 70% probability to have a semimajor axis between 2.5 and 3 au, a 33% probability to have an eccentricity smaller than 0.2 and a 45% probability to have an orbital inclination smaller than 10 degrees. Assuming the existence of 3,600 Ceres-size planetesimals in the inner part of the trans-Saturnian disk, consistent with the estimate of Nesvorny & Vokrouhlicky (2016) for the trans-Neptunian disk, our estimated capture probability and a final 80% depletion of the asteroid belt during the subsequent giant planet instability, lead to capture 1 Ceres in the asteroid belt, with a probability of 15%, 34%, and 51% to be located in the inner, middle and outer belt respectively.

The Classical Kuiper Belt is populated by a group of objects with low inclination orbits, reddish colors and usually belonging to a binary system. This so called Cold Classical Kuiper Belt is considered to have been formed in situ from primordial ice pebbles that coagulated into planetesimals hundreds of kilometers in diameter. According to this scenario, the accretion of pebbles into large planetesimals would have occurred through the streaming instability mechanism that would be effective in the primordial Solar System disk of gas and solids. Nevertheless other objects with the same color characteristics as those found in the Cold Classical Kuiper Belt can be encountered also past the 2:1 mean motion resonance with Neptune as scattered or detached objects. Here I propose a mechanism that can account for both the cold Classical Kuiper Belt objects and other reddish objects outside the Classical Kuiper Belt. According to the proposed scenario, reddish objects were primordially in the outer portion of the planetesimal disk which was however truncated somewhere below 42 au. In this manner the cold Classical Kuiper Belt and its scattered / detached counterpart were respectively transported outwards by a short range or slightly scattered to their present locations. Resonant objects were also formed by the same process. This mechanism is aimed at explaining the distribution of all objects that share the same color characteristics as coming from a common origin in the outer borders of the primordial planetesimal disk. According to the scenario here proposed the Cold Classical Kuiper Belt would have been formed around 4 au inside its present location with a total mass 20 to 100 times as large as its present value.

The dynamical structure of the Solar System can be explained by a period of orbital instability experienced by the giant planets. While a late instability was originally proposed to explain the Late Heavy Bombardment, recent work favors an early instability. We model the early dynamical evolution of the outer Solar System to self-consistently constrain the most likely timing of the instability. We first simulate the dynamical sculpting of the primordial outer planetesimal disk during the accretion of Uranus and Neptune from migrating planetary embryos during the gas disk phase, and determine the separation between Neptune and the inner edge of the planetesimal disk. We performed simulations with a range of migration histories for Jupiter. We find that, unless Jupiter migrated inwards by 10 AU or more, the instability almost certainly happened within 100 Myr of the start of Solar System formation. There are two distinct possible instability triggers. The first is an instability that is triggered by the planets themselves, with no appreciable influence from the planetesimal disk. Of those, the median instability time is $\sim4$Myr. Among self-stable systems -- where the planets are locked in a resonant chain that remains stable in the absence of a planetesimal's disk-- our self-consistently sculpted planetesimal disks nonetheless trigger a giant planet instability with a median instability time of 37-62 Myr for a reasonable range of migration histories of Jupiter. The simulations that give the latest instability times are those that invoked long-range inward migration of Jupiter from 15 AU or beyond; however these simulations over-excited the inclinations of Kuiper belt objects and are inconsistent with the present-day Solar System. We conclude on dynamical grounds that the giant planet instability is likely to have occurred early in Solar System history., Comment: 46 pages, 26 figures, Article reference YICAR_113605, https://authors.elsevier.com/tracking/article/details.do?aid=113605&jid=YICAR&surname=Ribeiro

Transneptunian objects (TNOs) are a source of invaluable information to access the history and evolution of the outer solar system. However, observing these faint objects is a difficult task. As a consequence, important properties such as size and albedo are known for only a small fraction of them. Now, with the results from deep sky surveys and the Gaia space mission, a new exciting era is within reach as accurate predictions of stellar occultations by numerous distant small solar system bodies become available. From them, diameters with kilometer accuracies can be determined. Albedos, in turn, can be obtained from diameters and absolute magnitudes. We use observations from the Dark Energy Survey (DES) from November 2012 until February 2016, amounting to 4292847 CCD frames. We searched them for all known small solar system bodies and recovered a total of 202 TNOs and Centaurs, 63 of which have been discovered by the DES collaboration until the date of this writing. Their positions were determined using the Gaia Data Release 2 as reference and their orbits were refined. Stellar occultations were then predicted using these refined orbits plus stellar positions from Gaia. These predictions are maintained, and updated, in a dedicated web service. The techniques developed here are also part of an ambitious preparation to use the data from the Large Synoptic Survey Telescope (LSST), that expects to obtain accurate positions and multifilter photometry for tens of thousands of TNOs., Comment: 25 pages, submitted to Astronomical Journal

The link between the dynamical evolution of the giant planets and the Kuiper Belt orbital structure can provide clues and insight about the dynamical history of the Solar System. The classical region of the Kuiper Belt has two populations (the cold and hot populations) with completely different physical and dynamical properties. These properties have been explained in the framework of a subset of the simulations of the Nice Model, in which Neptune remained on a low-eccentricity orbit (Neptune's eccentricity is never larger than 0.1) throughout the giant planet instability. However, recent simulations have showed that the remaining Nice model simulations, in which Neptune temporarily acquires a large-eccentricity orbit (larger than 0.1), are also consistent with the preservation of the cold population (inclination smaller than 4 degrees), if the latter formed in situ. However, the resulting a cold population showed in many of the simulations eccentricities larger than those observed for the real population. We focus on a short period of time which is characterized by Neptune's large eccentricity and a slow precession of Neptune's perihelion. We show that if self-gravity is considered in the disk, the precession rate of the particles longitude of perihelion is slowed down. This, combined with the effect of mutual scattering among the bodies, which spreads all orbital elements, allows some objects to return to low eccentricities. However, we show that if the cold population originally had a small total mass, this effect is negligible. Thus, we conclude that the only possibilities to keep at low eccentricity some cold-population objects during a high-eccentricity phase of Neptune are that (i) either Neptune's precession was rapid, as suggested by Batygin et al. (2011) or (ii) Neptune's slow precession phase was long enough to allow some particles to experience a full secular cycle.

The hypothesis of an additional planet in the outer Solar System has gained new support as a result of the confinement noted in the angular orbital elements of distant trans-Neptunian objects. Orbital parameters proposed for the external perturber suggest semimajor axes between 500 and 1000 au, perihelion distances between 200 and 400 au for masses between 10 and 20 $M_{\oplus}$. In this paper we study the possibility that lower perihelion distances for the additional planet can lead to angular confinements as observed in the population of objects with semimajor axes greater than 250 au and perihelion distances higher than 40 au. We performed numerical integrations of a set of particles subjected to the influence of the known planets and the putative perturber during the age of the Solar System and compared our outputs with the observed population through a statistical analysis. Our investigations showed that lower perihelion distances from the outer planet usually lead to more substantial confinements than higher ones, while retaining the Classical Kuiper Belt as well as the ratio of the number of detached with perihelion distances higher than 42 au to scattering objects in the range of semimajor axes from 100 au to 200 au.

The main asteroid belt (MB) is low in mass but dynamically excited. Here we propose a new mechanism to excite the MB during the giant planet ('Nice model') instability, which is expected to have featured repeated close encounters between Jupiter and one or more ice giants ('Jumping Jupiter' -- JJ). We show that, when Jupiter temporarily reaches a high enough level of excitation, both in eccentricity and inclination it induces strong forced vectors of eccentricity and inclination across the MB region. Because during the JJ instability Jupiter's orbit `jumps' around, the forced vectors keep changing both in magnitude and phase throughout the whole MB region. The entire cold primordial MB is thus excited as a natural outcome of the JJ instability. The level of such an excitation, however, is typically larger than the current orbital excitation observed in the MB. We show that the subsequent evolution of the Solar System is capable of reshaping the resultant over-excited MB to its present day orbital state, and that a strong mass depletion ($\sim$90$\%$) is associated to the JJ instability phase and its subsequent evolution throughout the age of the Solar System., Comment: Accepted for publication in The Astrophysical Journal

The origin of the orbital structure of the cold component of the Kuiper belt is still a hot subject of investigation. Several features of the solar system suggest that the giant planets underwent a phase of global dynamical instability, but the actual dynamical evolution of the planets during the instability is still debated. To explain the structure of the cold Kuiper belt, Nesvorny (2015, AJ 150,68) argued for a soft instability, during which Neptune never achieved a very eccentric orbit. Here we investigate the possibility of a more violent instability, from an initially more compact fully resonant configuration of 5 giant planets. We show that the orbital structure of the cold Kuiper belt can be reproduced quite well provided that the cold population formed in situ, with an outer edge between 44 and 45 au and never had a large mass.

Recent works on planetary migration show that the orbital structure of the Kuiper belt can be very well reproduced if before the onset of the planetary instability Neptune underwent a long-range planetesimal-driven migration up to $\sim$28 au. However, considering that all giant planets should have been captured in mean motion resonances among themselves during the gas-disk phase, it is not clear whether such a very specific evolution for Neptune is possible, nor whether the instability could have happened at late times. Here, we first investigate which initial resonant configuration of the giant planets can be compatible with Neptune being extracted from the resonant chain and migrating to $\sim$28 au before that the planetary instability happened. We address the late instability issue by investigating the conditions where the planets can stay in resonance for about 400 My. Our results indicate that this can happen only in the case where the planetesimal disk is beyond a specific minimum distance $\delta_{stab}$ from Neptune. Then, if there is a sufficient amount of dust produced in the planetesimal disk, that drifts inwards, Neptune can enter in a slow dust-driven migration phase for hundreds of Mys until it reaches a critical distance $\delta_{mig}$ from the disk. From that point, faster planetesimal-driven migration takes over and Neptune continues migrating outward until the instability happens. We conclude that, although an early instability reproduces more easily the evolution of Neptune required to explain the structure of the Kuiper belt, such evolution is also compatible with a late instability., Comment: Accepted for publication in AJ

The Asteroid Belt is characterized by the radial mixing of bodies with different physical properties, a very low mass compared to Minimum Mass Solar Nebula expectations and has an excited orbital distribution. Models of the evolution of the Asteroid Belt show that the origin of its structure is strongly linked to the process of terrestrial planet formation. The Grand Tack model presents a possible solution to the conundrum of reconciling the small mass of Mars with the properties of the Asteroid Belt, including the mass depletion, radial mixing and orbital excitation. However, while the inclination distribution produced in the Grand Tack model is in good agreement with the one observed, the eccentricity distribution is skewed towards values larger than those found today. Here, we evaluate the evolution of the orbital properties of the Asteroid Belt from the end of the Grand Tack model (at the end of the gas nebula phase when planets emerge from the dispersing gas disk), throughout the subsequent evolution of the Solar System including an instability of the Giant Planets approximately 400 My later. Before the instability, the terrestrial planets were modeled on dynamically cold orbits with Jupiter and Saturn locked in a 3:2 mean motion resonance. The model continues for an additional 4.1 Gy after the giant planet instability. Our results show that the eccentricity distribution obtained in the Grand Tack model evolves towards one very similar to that currently observed, and the semimajor axis distribution does the same. The inclination distribution remains nearly unchanged with a slight preference for depletion at low inclination; this leads to the conclusion that the inclination distribution at the end of the Grand Tack is a bit over-excited., Comment: published on Icarus

We evaluate the effects of a distant planet, commonly known as planet 9, on the dynamics of the giant planets of the Solar System. We find that, given the large distance of planet 9, the dynamics of the inner giant planets can be decomposed into a classic Lagrange-Laplace dynamics relative to their own invariant plane (the plane orthogonal to their total angular momentum vector) and a slow precession of said plane relative to the total angular momentum vector of the Solar System, including planet 9. Under some specific configurations for planet 9, this precession can explain the current tilt of approximately 6 degrees between the invariant plane of the giant planets and the solar equator. An analytical model is developed to map the evolution of the inclination of the inner giant planets' invariant plane as a function of the planet 9's mass, inclination, eccentricity and semimajor axis, and some numerical simulations of the equations of motion of the giant planets and planet 9 are performed to validate our analytical approach. The longitude of the ascending node of planet 9 is found to be linked to the longitude of the ascending node of the giant planets' invariant plane, which also constrain the longitude of the node of planet 9 on the ecliptic. Some of the planet 9 configurations that allow explaining the current solar tilt are compatible with those proposed to explain the orbital confinement of the most distant Kuiper belt objects. Thus, this work on the one hand gives an elegant explanation for the current tilt between the invariant plane of the inner giant planets and the solar equator and, on the other hand, adds new constraints to the orbital elements of planet 9., Comment: manuscript #: AAS01708, submitted on July 12, 2016