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Sean N. Raymond - One of the best experts on this subject based on the ideXlab platform.
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Formation of Terrestrial Planets in eccentric and inclined giant planet systems
Astronomy & Astrophysics, 2018Co-Authors: Sotiris Sotiriadis, Anne-sophie Libert, Sean N. RaymondAbstract:Aims. Evidence of mutually inclined planetary orbits has been reported for giant Planets in recent years. Here we aim to study the impact of eccentric and inclined massive giant Planets on the Terrestrial planet formation process, and investigate whether it can possibly lead to the formation of inclined Terrestrial Planets. Methods. We performed 126 simulations of the late-stage planetary accretion in eccentric and inclined giant planet systems. The physical and orbital parameters of the giant planet systems result from n-body simulations of three giant Planets in the late stage of the gas disc, under the combined action of Type II migration and planet-planet scattering. Fourteen two- and three-planet configurations were selected, with diversified masses, semi-major axes (resonant configurations or not), eccentricities, and inclinations (including coplanar systems) at the dispersal of the gas disc. We then followed the gravitational interactions of these systems with an inner disc of planetesimals and embryos (nine runs per system), studying in detail the final configurations of the formed Terrestrial Planets. Results. In addition to the well-known secular and resonant interactions between the giant Planets and the outer part of the disc, giant Planets on inclined orbits also strongly excite the planetesimals and embryos in the inner part of the disc through the combined action of nodal resonance and the Lidov–Kozai mechanism. This has deep consequences on the formation of Terrestrial Planets. While coplanar giant systems harbour several Terrestrial Planets, generally as massive as the Earth and mainly on low-eccentric and low-inclined orbits, Terrestrial Planets formed in systems with mutually inclined giant Planets are usually fewer, less massive ( M ⊕ ), and with higher eccentricities and inclinations. This work shows that Terrestrial Planets can form on stable inclined orbits through the classical accretion theory, even in coplanar giant planet systems emerging from the disc phase.
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Formation of Terrestrial Planets in eccentric and inclined giant planet systems
Astronomy and Astrophysics - A&A, 2018Co-Authors: Sotiris Sotiriadis, Anne-sophie Libert, Sean N. Raymond, Sean N. RaymondAbstract:Evidence of mutually inclined planetary orbits has been reported for giant Planets these last years. Here we aim to study the impact of eccentric and inclined massive giant Planets on the Terrestrial planet formation process, and investigate whether it can possibly lead to the existence of inclined Terrestrial Planets. We have performed 126 simulations of the late-stage planetary accretion in eccentric and inclined giant planet systems. The physical and orbital parameters of the giant planet systems result from n-body simulations of three giant Planets in the late stage of the gas disc, under the combined action of Type II migration and planet-planet scattering. Fourteen two- and three-planet configurations have been selected, with diversified masses, semi-major axes (resonant configurations or not), eccentricities and inclinations (including coplanar systems) at the dispersal of the gas disc. We have then followed the gravitational interactions of these systems with an inner disc of planetesimals and embryos (9 runs per system), studying in detail the final configurations of the formed Terrestrial Planets. While coplanar giant systems harbour several Terrestrial Planets, generally as massive as the Earth and mainly on low eccentric and low inclined orbits, Terrestrial Planets formed in systems with mutually inclined giant Planets are usually fewer, less massive (
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Formation of Terrestrial Planets
2018Co-Authors: A. Izidoro, Sean N. RaymondAbstract:The past decade has seen major progress in our understanding of Terrestrial planet formation. Yet key questions remain. In this review we first address the growth of 100 km-scale planetesimals as a consequence of dust coagulation and concentration, with current models favoring the streaming instability. Planetesimals grow into Mars-sized (or larger) planetary embryos by a combination of pebble- and planetesimal accretion. Models for the final assembly of the inner Solar System must match constraints related to the Terrestrial Planets and asteroids including their orbital and compositional distributions and inferred growth timescales. Two current models -- the Grand-Tack and low-mass (or empty) primordial asteroid belt scenarios -- can each match the empirical constraints but both have key uncertainties that require further study. We present formation models for close-in super-Earths -- the closest current analogs to our own Terrestrial Planets despite their very different formation histories -- and for Terrestrial exoPlanets in gas giant systems. We explain why super-Earth systems cannot form in-situ but rather may be the result of inward gas-driven migration followed by the disruption of compact resonant chains. The Solar System is unlikely to have harbored an early system of super-Earths; rather, Jupiter's early formation may have blocked the ice giants' inward migration. Finally, we present a chain of events that may explain why our Solar System looks different than more than 99\% of exoplanet systems.
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Dynamical and collisional constraints on a stochastic late veneer on the Terrestrial Planets
Icarus, 2013Co-Authors: Sean N. Raymond, Hilke E. Schlichting, F. Hersant, Franck SelsisAbstract:Given their tendency to be incorporated into the core during differentiation, the highly-siderophile elements (HSEs) in Earth's mantle are thought to have been accreted as a 'late veneer' after the end of the giant impact phase. Bottke et al (2010) proposed that the large Earth-to-Moon HSE abundance ratio can be explained if the late veneer was characterized by large (D = 1000-4000km) impactors. Here we simulate the evolution of the Terrestrial Planets during a stochastic late veneer phase from the end of accretion until the start of the late heavy bombardment ~500 Myr later. We show that a late veneer population of 0.05 Earth masses dominated by large (D > 1000km) bodies naturally delivers a ~0.01 Earth mass veneer to Earth, consistent with constraints. The eccentricities and inclinations of the Terrestrial Planets are excited by close encounters with the largest late veneer bodies. We find the best agreement with their post-veneer orbits if either a) the Terrestrial Planets' pre-veneer angular momentum deficit AMD_0 was less than half of the current one AMD_now, or b) AMD_0
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building Terrestrial Planets
arXiv: Earth and Planetary Astrophysics, 2012Co-Authors: Alessandro Morbidelli, Sean N. Raymond, Jonathan I Lunine, David P O Brien, Kevin J WalshAbstract:This paper reviews our current understanding of Terrestrial Planets formation. The focus is on computer simulations of the dynamical aspects of the accretion process. Throughout the chapter, we combine the results of these theoretical models with geochemical, cosmochemical and chronological constraints, in order to outline a comprehensive scenario of the early evolution of our Solar System. Given that the giant Planets formed first in the protoplanetary disk, we stress the sensitive dependence of the Terrestrial planet accretion process on the orbital architecture of the giant Planets and on their evolution. This suggests a great diversity among the Terrestrial Planets populations in extrasolar systems. Issues such as the cause for the different masses and accretion timescales between Mars and the Earth and the origin of water (and other volatiles) on our planet are discussed at depth.
Ramon Brasser - One of the best experts on this subject based on the ideXlab platform.
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Isotopically distinct Terrestrial Planets via local accretion
Icarus, 2021Co-Authors: Jingyi Mah, Ramon BrasserAbstract:Abstract Combining isotopic constraints from meteorite data with dynamical models of planet formation proves to be advantageous in identifying the best model for Terrestrial planet formation. Prior studies have shown that the probability of reproducing the distinct isotopic compositions of the Earth and Mars for both classical and Grand Tack models is very low. In the framework of the Grand Tack model, for Mars to be isotopically different from the Earth, it had to form under very specific conditions. Here, we subjected a fairly new and unexplored model—the depleted disc model—to the test. It presupposes that the region in the inner protoplanetary disc from Mars’ orbit and beyond is depleted in mass such that Mars is left with insufficient material to grow to a larger size. Our aim is to test the whether the distinct isotopic compositions of the Earth and Mars are a natural outcome of this model. We found that the Terrestrial Planets accrete material mostly locally and have feeding zones that are sufficiently distinct. The Earth and Mars, and by extension, Venus, can have distinct isotopic compositions if there is an isotopic gradient in the Terrestrial planet region of the protoplanetary disc. Our results suggest that the material in the inner Solar System most likely did not undergo substantial mixing that homogenised the potential isotopic gradient, in contrast to the Grand Tack model where the feeding zones of the Terrestrial Planets are nearly identical due to the mixing of material by Jupiter’s migration.
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Feedstocks of the Terrestrial Planets
Space Science Reviews, 2018Co-Authors: Richard W. Carlson, Ramon Brasser, Qing-zhu Yin, M. Fischer-gödde, Liping QinAbstract:The processes of planet formation in our Solar System resulted in a final product of a small number of discreet Planets and planetesimals characterized by clear compositional distinctions. A key advance on this subject was provided when nucleosynthetic isotopic variability was discovered between different meteorite groups and the Terrestrial Planets. This information has now been coupled with theoretical models of planetesimal growth and giant planet migration to better understand the nature of the materials accumulated into the Terrestrial Planets. First order conclusions include that carbonaceous chondrites appear to contribute a much smaller mass fraction to the Terrestrial Planets than previously suspected, that gas-driven giant planet migration could have pushed volatile-rich material into the inner Solar System, and that planetesimal formation was occurring on a sufficiently rapid time scale that global melting of asteroid-sized objects was instigated by radioactive decay of 26Al. The isotopic evidence highlights the important role of enstatite chondrites, or something with their mix of nucleosynthetic components, as feedstock for the Terrestrial Planets. A common degree of depletion of moderately volatile elements in the Terrestrial Planets points to a mechanism that can effectively separate volatile and refractory elements over a spatial scale the size of the whole inner Solar System. The large variability in iron to silicon ratios between both different meteorite groups and between the Terrestrial Planets suggests that mechanisms that can segregate iron metal from silicate should be given greater importance in future investigations. Such processes likely include both density separation of small grains in the nebula, but also preferential impact erosion of either the mantle or core from differentiated Planets/planetesimals. The latter highlights the important role for giant impacts and collisional erosion during the late stages of planet formation.
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Constraining the primordial orbits of the Terrestrial Planets
Monthly Notices of the Royal Astronomical Society, 2013Co-Authors: Ramon Brasser, Kevin J Walsh, David NesvornýAbstract:Evidence in the Solar System suggests that the giant Planets underwent an epoch of radial migration that was very rapid, with an e-folding timescale shorter than 1~Myr. It is probable that the cause of this migration was that the giant Planets experienced an orbital instability that caused them to encounter each other, resulting in radial migration. Several works suggest that this dynamical instability occurred `late', long after all the Planets had formed and the solar nebula had dissipated. Assuming that the Terrestrial Planets had already formed, then their orbits would have been affected by the migration of the giant Planets. As a result, how did the orbits of the Terrestrial Planets change? And can we use this migration to obtain information on the primordial orbits of the Terrestrial Planets? We directly model a large number of Terrestrial planet systems and their response to giant planet migration. We study the change in the Angular Momentum Deficit (AMD) of the terrstrials. We conclude that the primordial AMD should have been lower than ~70\% of the current value, but higher than 10\%. We find that a scenario with five giant Planets better satisfies the orbital constraints of the Terrestrial Planets. We predict that Mars was initially on an eccentric and inclined orbit while the orbits of Mercury, Venus and Earth were more circular and coplanar. The lower primordial dynamical excitement and the peculiar partitioning between Planets impose new constraints for Terrestrial planet formation simulations.
Jonathan I Lunine - One of the best experts on this subject based on the ideXlab platform.
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building Terrestrial Planets
arXiv: Earth and Planetary Astrophysics, 2012Co-Authors: Alessandro Morbidelli, Sean N. Raymond, Jonathan I Lunine, David P O Brien, Kevin J WalshAbstract:This paper reviews our current understanding of Terrestrial Planets formation. The focus is on computer simulations of the dynamical aspects of the accretion process. Throughout the chapter, we combine the results of these theoretical models with geochemical, cosmochemical and chronological constraints, in order to outline a comprehensive scenario of the early evolution of our Solar System. Given that the giant Planets formed first in the protoplanetary disk, we stress the sensitive dependence of the Terrestrial planet accretion process on the orbital architecture of the giant Planets and on their evolution. This suggests a great diversity among the Terrestrial Planets populations in extrasolar systems. Issues such as the cause for the different masses and accretion timescales between Mars and the Earth and the origin of water (and other volatiles) on our planet are discussed at depth.
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impact regimes and post formation sequestration processes implications for the origin of heavy noble gases in Terrestrial Planets
The Astrophysical Journal, 2010Co-Authors: Olivier Mousis, Jonathan I Lunine, Jeanmarc Petit, S Picaud, Bernard Schmitt, Didier Marquer, Jonathan Horner, C ThomasAbstract:The difference between the measured atmospheric abundances of neon, argon, krypton, and xenon for Venus, Earth, and Mars is striking. Because these abundances drop by at least 2 orders of magnitude as one moves outward from Venus to Mars, the study of the origin of this discrepancy is a key issue that must be explained if we are to fully understand the different delivery mechanisms of the volatiles accreted by the Terrestrial Planets. In this work, we aim to investigate whether it is possible to quantitatively explain the variation of the heavy noble gas abundances measured on Venus, Earth, and Mars, assuming that cometary bombardment was the main delivery mechanism of these noble gases to the Terrestrial Planets. To do so, we use recent dynamical simulations that allow the study of the impact fluxes of comets upon the Terrestrial Planets during the course of their formation and evolution. Assuming that the mass of noble gases delivered by comets is proportional to the rate at which they collide with the Terrestrial Planets, we show that the krypton and xenon abundances in Venus and Earth can be explained in a manner consistent with the hypothesis of cometary bombardment. In order to explain the krypton and xenon abundance differences between Earth and Mars, we need to invoke the presence of large amounts of CO2-dominated clathrates in the Martian soil that would have efficiently sequestered these noble gases. Two different scenarios based on our model can also be used to explain the differences between the neon and argon abundances of the Terrestrial Planets. In the first scenario, cometary bombardment of these Planets would have occurred at epochs contemporary with the existence of their primary atmospheres. Comets would have been the carriers of argon, krypton, and xenon, while neon would have been gravitationally captured by the Terrestrial Planets. In the second scenario, we consider impacting comets that contained significantly smaller amounts of argon, an idea supported by predictions of noble gas abundances in these bodies, provided that they formed from clathrates in the solar nebula. In this scenario, neon and argon would have been supplied to the Terrestrial Planets via the gravitational capture of their primary atmospheres whereas the bulk of their krypton and xenon would have been delivered by comets.
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impact regimes and post formation sequestration processes implications for the origin of heavy noble gases in Terrestrial Planets
arXiv: Earth and Planetary Astrophysics, 2010Co-Authors: Olivier Mousis, Jonathan I Lunine, Jeanmarc Petit, S Picaud, Bernard Schmitt, Didier Marquer, Jonathan Horner, C ThomasAbstract:The difference between the measured atmospheric abundances of neon, argon, krypton and xenon for Venus, the Earth and Mars is striking. Because these abundances drop by at least two orders of magnitude as one moves outward from Venus to Mars, the study of the origin of this discrepancy is a key issue that must be explained if we are to fully understand the different delivery mechanisms of the volatiles accreted by the Terrestrial Planets. In this work, we aim to investigate whether it is possible to quantitatively explain the variation of the heavy noble gas abundances measured on Venus, the Earth and Mars, assuming that cometary bombardment was the main delivery mechanism of these noble gases to the Terrestrial Planets. To do so, we use recent dynamical simulations that allow the study of the impact fluxes of comets upon the Terrestrial Planets during the course of their formation and evolution. Assuming that the mass of noble gases delivered by comets is proportional to rate at which they collide with the Terrestrial Planets, we show that the krypton and xenon abundances in Venus and the Earth can be explained in a manner consistent with the hypothesis of cometary bombardment. In order to explain the krypton and xenon abundance differences between the Earth and Mars, we need to invoke the presence of large amounts of CO2-dominated clathrates in the Martian soil that would have efficiently sequestered these noble gases.
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The formation and habitability of Terrestrial Planets in the presence of close-in giant Planets
Icarus, 2005Co-Authors: Sean N. Raymond, Thomas R. Quinn, Jonathan I LunineAbstract:‘Hot jupiters,’ giant Planets with orbits very close to their parent stars, are thought to form farther away and migrate inward via interactions with a massive gas disk. If a giant planet forms and migrates quickly, the planetesimal population has time to re-generate in the lifetime of the disk and Terrestrial Planets may form [P.J. Armitage, A reduced efficiency of Terrestrial planet formation following giant planet migration, Astrophys. J. 582 (2003) L47–L50]. We present results of simulations of Terrestrial planet formation in the presence of hot/warm jupiters, broadly defined as having orbital radii 0.5 AU. We show that Terrestrial Planets similar to those in the Solar System can form around stars with hot/warm jupiters, and can have water contents equal to or higher than the Earth’s. For small orbital radii of hot jupiters (e.g., 0.15, 0.25 AU) potentially habitable Planets can form, but for semi-major axes of 0.5 AU or greater their formation is suppressed. We show that the presence of an outer giant planet such as Jupiter does not enhance the water content of the Terrestrial Planets, but rather decreases their formation and water delivery timescales. We speculate that asteroid belts may exist interior to the Terrestrial Planets in systems with close-in giant Planets. 2005 Elsevier Inc. All rights reserved.
Andrew Willes - One of the best experts on this subject based on the ideXlab platform.
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Radio emissions from Terrestrial Planets around white dwarfs
Astronomy & Astrophysics, 2005Co-Authors: Andrew WillesAbstract:Terrestrial Planets in close orbits around magnetic white dwarf stars are potential electron-cyclotron maser sources, by analogy to planetary radio emissions generated from the electrodynamic interaction between Jupiter and the Galilean moons. We present predictions of radio flux densities and the number of detectable white-dwarf/Terrestrial-planet systems, and discuss a scenario for their formation.
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Radio Emissions from Terrestrial Planets around White Dwarfs
Symposium - International Astronomical Union, 2004Co-Authors: Andrew WillesAbstract:Terrestrial Planets in close orbits around magnetic white dwarf stars can be electron-cyclotron maser sources, by analogy to planetary radio emissions generated from the electrodynamic interaction between Jupiter and the Galilean moons. We present predictions of the radio flux densities from white-dwarf/Terrestrial-planet systems and discuss a scenario for the formation of these systems.
C Thomas - One of the best experts on this subject based on the ideXlab platform.
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impact regimes and post formation sequestration processes implications for the origin of heavy noble gases in Terrestrial Planets
The Astrophysical Journal, 2010Co-Authors: Olivier Mousis, Jonathan I Lunine, Jeanmarc Petit, S Picaud, Bernard Schmitt, Didier Marquer, Jonathan Horner, C ThomasAbstract:The difference between the measured atmospheric abundances of neon, argon, krypton, and xenon for Venus, Earth, and Mars is striking. Because these abundances drop by at least 2 orders of magnitude as one moves outward from Venus to Mars, the study of the origin of this discrepancy is a key issue that must be explained if we are to fully understand the different delivery mechanisms of the volatiles accreted by the Terrestrial Planets. In this work, we aim to investigate whether it is possible to quantitatively explain the variation of the heavy noble gas abundances measured on Venus, Earth, and Mars, assuming that cometary bombardment was the main delivery mechanism of these noble gases to the Terrestrial Planets. To do so, we use recent dynamical simulations that allow the study of the impact fluxes of comets upon the Terrestrial Planets during the course of their formation and evolution. Assuming that the mass of noble gases delivered by comets is proportional to the rate at which they collide with the Terrestrial Planets, we show that the krypton and xenon abundances in Venus and Earth can be explained in a manner consistent with the hypothesis of cometary bombardment. In order to explain the krypton and xenon abundance differences between Earth and Mars, we need to invoke the presence of large amounts of CO2-dominated clathrates in the Martian soil that would have efficiently sequestered these noble gases. Two different scenarios based on our model can also be used to explain the differences between the neon and argon abundances of the Terrestrial Planets. In the first scenario, cometary bombardment of these Planets would have occurred at epochs contemporary with the existence of their primary atmospheres. Comets would have been the carriers of argon, krypton, and xenon, while neon would have been gravitationally captured by the Terrestrial Planets. In the second scenario, we consider impacting comets that contained significantly smaller amounts of argon, an idea supported by predictions of noble gas abundances in these bodies, provided that they formed from clathrates in the solar nebula. In this scenario, neon and argon would have been supplied to the Terrestrial Planets via the gravitational capture of their primary atmospheres whereas the bulk of their krypton and xenon would have been delivered by comets.
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impact regimes and post formation sequestration processes implications for the origin of heavy noble gases in Terrestrial Planets
arXiv: Earth and Planetary Astrophysics, 2010Co-Authors: Olivier Mousis, Jonathan I Lunine, Jeanmarc Petit, S Picaud, Bernard Schmitt, Didier Marquer, Jonathan Horner, C ThomasAbstract:The difference between the measured atmospheric abundances of neon, argon, krypton and xenon for Venus, the Earth and Mars is striking. Because these abundances drop by at least two orders of magnitude as one moves outward from Venus to Mars, the study of the origin of this discrepancy is a key issue that must be explained if we are to fully understand the different delivery mechanisms of the volatiles accreted by the Terrestrial Planets. In this work, we aim to investigate whether it is possible to quantitatively explain the variation of the heavy noble gas abundances measured on Venus, the Earth and Mars, assuming that cometary bombardment was the main delivery mechanism of these noble gases to the Terrestrial Planets. To do so, we use recent dynamical simulations that allow the study of the impact fluxes of comets upon the Terrestrial Planets during the course of their formation and evolution. Assuming that the mass of noble gases delivered by comets is proportional to rate at which they collide with the Terrestrial Planets, we show that the krypton and xenon abundances in Venus and the Earth can be explained in a manner consistent with the hypothesis of cometary bombardment. In order to explain the krypton and xenon abundance differences between the Earth and Mars, we need to invoke the presence of large amounts of CO2-dominated clathrates in the Martian soil that would have efficiently sequestered these noble gases.
