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Last name: MORBIDELLI
First name: Alessandro
International audience
The apparent regularity of the motion of the giant planets of our solar system suggested for decades that said planets formed onto orbits similar to the current ones and that nothing dramatic ever happened during their lifetime. The discovery of extra-solar planets showed astonishingly that the orbital structure of our planetary system is not...
Since the discovery of the first extra-solar planets, we are confronted with the puzzling diversity of planetary systems. Processes like planet radial migration in gas-disks and planetary orbital instabilities, often invoked to explain the exotic orbits of the extra-solar planets, at first sight do not seem to have played a role in our system....
International audience
Classical simulations of the formation and evolution of the Oort cloud generally encounter two problems. The most severe one is simulations systematically predicting an Oort cloud to Scattered Disc population ratio that is much lower than inferred from observations. The analysis was traditionally done for long-period comets (LPCs) with total...
International audience
International audience
International audience
Over the past two decades, large strides have been made in the field of planet formation. Yet fundamental questions remain. Here we review our state of understanding of five fundamental bottlenecks in planet formation. These are: 1) the structure and evolution of protoplanetary disks; 2) the growth of the first planetesimals; 3) orbital...
The `Grand Tack' model proposes that the inner Solar System was sculpted by the giant planets' orbital migration in the gaseous protoplanetary disk. Jupiter first migrated inward then Jupiter and Saturn migrated back outward together. If Jupiter's turnaround or "tack" point was at ~1.5 AU the inner disk of terrestrial building blocks would have...
The giant planets of our solar system possess envelopes consisting mainly of hydrogen and helium but are also significantly enriched in heavier elements relatively to our Sun. In order to better constrain how these heavy elements have been delivered, we quantify the amount accreted during the so-called "late heavy bombardment", at a time when...
Context. It is well known that asteroids and comets fall into the Sun. Metal pollution of white dwarfs and transient spectroscopic signatures of young stars like β-Pic provide growing evidence that extra solar planetesimals can attain extreme orbital eccentricities and fall into their parent stars.Aims. We aim to develop a general,...
Early dynamical evolution of close-in planetary systems is shaped by an intricate combination of planetary gravitational interactions, orbital migration, and dissipative effects. While the process of convergent orbital migration is expected to routinely yield resonant planetary systems, previous analyses have shown that the semi-major axes of...
Aims. The near-Earth asteroid population suggests the existence of an inner main belt source of asteroids that belongs to the spectroscopic X complex and has moderate albedos. The identification of such a source has been lacking so far. We argue that the most probable source is one or more collisional asteroid families that have escaped...
International audience
In current dynamical evolution models aiming at reproducing the orbital structure of the Kuiper Belt, the giant planets start from a compact multiresonant orbital configuration and migrate to their current positions by interacting with a planetesimal disk extending beyond the orbit of Neptune. In order to stop the migration of Neptune at 30 AU...
During the pre-instability period following the disappearance of the protoplanetary gas disk, the giant planets were in a compact multiresonant orbital configuration, before starting to migrate by interacting with a planetesimal disk extending beyond the orbit of Neptune. It is commonly accepted that the disk was divided into two parts: a...
Super-Earths with orbital periods less than 100 days are extremely abundant around Sun-like stars. It is unlikely that these planets formed at their current locations. Rather, they likely formed at large distances from the star and subsequently migrated inward. Here we use N-body simulations to study the effect of super-Earths on the accretion...
The dynamically hot and cold populations of the Kuiper Belt probably formed from two distinct regions of the Solar System. The former originated from a massive planetesimal disk extending from the primordial position of Neptune to ∼30 AU and the latter from a light extension of the planetesimal disk, prolonging beyond 30 AU. Previous studies on...
Planets of 1-4 times Earth's size on orbits shorter than 100 days exist around 30-50% of all Sun-like stars. These ``hot super-Earths'' (or ``mini-Neptunes''), or their building blocks, might have formed on wider orbits and migrated inward due to interactions with the gaseous protoplanetary disk. The Solar System is statistically unusual in its...
Planets of 1–4 times Earth's size on orbits shorter than 100 days exist around 30–50% of all Sun-like stars. In fact, the Solar System is particularly outstanding in its lack of "hot super-Earths" (or "mini-Neptunes"). These planets —or their building blocks—may have formed on wider orbits and migrated inward due to interactions with the...
In current dynamical evolution models aiming at reproducing the orbital structure of the Kuiper Belt, the giant planets start from a compact multiresonant orbital configuration and migrate to their current positions by interacting with a planetesimal disk extending beyond the orbit of Neptune. In order to stop the migration of Neptune at 30 AU...
Super-Earths with orbital periods less than 100 days are extremely abundant around Sun-like stars. It is unlikely that these planets formed at their current locations. Rather, they likely formed at large distances from the star and subsequently migrated inward. In this work we use N-body simulations to study the effect of super-Earths on the...