Sean Raymond | Université Bordeaux (original) (raw)
Papers by Sean Raymond
Icarus, Jan 1, 2009
To date, no accretion model has succeeded in reproducing all observed constraints in the inner So... more To date, no accretion model has succeeded in reproducing all observed constraints in the inner Solar System. These constraints include 1) the orbits, in particular the small eccentricities, and 2) the masses of the terrestrial planets -Mars' relatively small mass in particular has not been adequately reproduced in previous simulations; 3) the formation timescales of Earth and Mars, as interpreted from Hf/W isotopes; 4) the bulk structure of the asteroid belt, in particular the lack of an imprint of planetary embryo-sized objects; and 5) Earth's relatively large water content, assuming that it was delivered in the form of water-rich primitive asteroidal material. Here we present results of 40 high-resolution (N=1000-2000) dynamical simulations of late-stage planetary accretion with the goal of reproducing these constraints, although neglecting the planet Mercury. We assume that Jupiter and Saturn are fully-formed at the start of each simulation, and test orbital configurations that are both consistent with and contrary to the "Nice model." We find that a configuration with Jupiter and Saturn on circular orbits forms low-eccentricity terrestrial planets and a water-rich Earth on the correct timescale, but Mars' mass is too large by a factor of 5-10 and embryos are often stranded in the asteroid belt. A configuration with Jupiter and Saturn in their current locations but with slightly higher initial eccentricities (e = 0.07 − 0.1) produces a small Mars, an embryo-free asteroid belt, and a reasonable Earth analog but rarely allows water delivery to Earth. None of the configurations we tested reproduced all the observed constraints. Our simulations leave us with a problem: we can reasonably satisfy the observed constraints (except for Earth's water) with a configuration of Jupiter and Saturn that is at best marginally consistent with models of the outer Solar System, as it does not allow for any outer planet migration after a few Myr. Alternately, giant planet configurations which are consistent with the Nice model fail to reproduce Mars' small size.
Nature, Jan 1, 2011
1 were susceptible to disk-driven migration on timescales of only ∼100 Kyr. 2 Hydrodynamical simu... more 1 were susceptible to disk-driven migration on timescales of only ∼100 Kyr. 2 Hydrodynamical simulations show that these giant planets can undergo a two-stage, inward-then-outward, migration. 3-5 The terrestrial planets finished accreting much later, 6 and their characteristics, including Mars' small mass, are best reproduced starting from a planetesimal disk with an outer edge at ∼1 AU. 7, 8 Here we present simulations of the early Solar System that show how the inward migration of Jupiter to 1.5 AU, and its subsequent outward migration, leads to a planetesimal disk truncated at 1 AU, from which the terrestrial planets form over the next 30-50 million years, with a correct Earth/Mars mass ratio. Scattering by Jupiter initially empties, but then repopulates the asteroid belt, with inner-belt bodies originating between 1-3 AU and outer belt bodies originating between and beyond the giant planets. This explains the significant compositional differences across the asteroid belt. The key aspect missing from previous models of terrestrial planet formation is an inward, and subsequent outward, migration of Jupiter. We conclude that the behaviour of our giant planets, characterized by substantial radial migration, is more similar to that inferred for extra-solar planets than previously thought.
The Astrophysical Journal, Jan 1, 2008
The Astrophysical …, Jan 1, 2008
The Astronomical …, Jan 1, 2007
The Astronomical …, Jan 1, 2007
The Astronomical …, Jan 1, 2007
Public reporting burden for the collection of information is estimated to average 1 hour per resp... more Public reporting burden for the collection of information is estimated to average 1 hour per response, including the time for reviewing instructions, searching existing data sources, gathering and maintaining the data needed, and completing and reviewing the collection of information. Send comments regarding this burden estimate or any other aspect of this collection of information, including suggestions for reducing this burden, to Washington Headquarters Services, Directorate for Information Operations and Reports, 1215 Jefferson Davis Highway, Suite 1204, Arlington VA 22202-4302. Respondents should be aware that notwithstanding any other provision of law, no person shall be subject to a penalty for failing to comply with a collection of information if it does not display a currently valid OMB control number.
Icarus, Jan 1, 2009
To date, no accretion model has succeeded in reproducing all observed constraints in the inner So... more To date, no accretion model has succeeded in reproducing all observed constraints in the inner Solar System. These constraints include 1) the orbits, in particular the small eccentricities, and 2) the masses of the terrestrial planets -Mars' relatively small mass in particular has not been adequately reproduced in previous simulations; 3) the formation timescales of Earth and Mars, as interpreted from Hf/W isotopes; 4) the bulk structure of the asteroid belt, in particular the lack of an imprint of planetary embryo-sized objects; and 5) Earth's relatively large water content, assuming that it was delivered in the form of water-rich primitive asteroidal material. Here we present results of 40 high-resolution (N=1000-2000) dynamical simulations of late-stage planetary accretion with the goal of reproducing these constraints, although neglecting the planet Mercury. We assume that Jupiter and Saturn are fully-formed at the start of each simulation, and test orbital configurations that are both consistent with and contrary to the "Nice model." We find that a configuration with Jupiter and Saturn on circular orbits forms low-eccentricity terrestrial planets and a water-rich Earth on the correct timescale, but Mars' mass is too large by a factor of 5-10 and embryos are often stranded in the asteroid belt. A configuration with Jupiter and Saturn in their current locations but with slightly higher initial eccentricities (e = 0.07 − 0.1) produces a small Mars, an embryo-free asteroid belt, and a reasonable Earth analog but rarely allows water delivery to Earth. None of the configurations we tested reproduced all the observed constraints. Our simulations leave us with a problem: we can reasonably satisfy the observed constraints (except for Earth's water) with a configuration of Jupiter and Saturn that is at best marginally consistent with models of the outer Solar System, as it does not allow for any outer planet migration after a few Myr. Alternately, giant planet configurations which are consistent with the Nice model fail to reproduce Mars' small size.
Nature, Jan 1, 2011
1 were susceptible to disk-driven migration on timescales of only ∼100 Kyr. 2 Hydrodynamical simu... more 1 were susceptible to disk-driven migration on timescales of only ∼100 Kyr. 2 Hydrodynamical simulations show that these giant planets can undergo a two-stage, inward-then-outward, migration. 3-5 The terrestrial planets finished accreting much later, 6 and their characteristics, including Mars' small mass, are best reproduced starting from a planetesimal disk with an outer edge at ∼1 AU. 7, 8 Here we present simulations of the early Solar System that show how the inward migration of Jupiter to 1.5 AU, and its subsequent outward migration, leads to a planetesimal disk truncated at 1 AU, from which the terrestrial planets form over the next 30-50 million years, with a correct Earth/Mars mass ratio. Scattering by Jupiter initially empties, but then repopulates the asteroid belt, with inner-belt bodies originating between 1-3 AU and outer belt bodies originating between and beyond the giant planets. This explains the significant compositional differences across the asteroid belt. The key aspect missing from previous models of terrestrial planet formation is an inward, and subsequent outward, migration of Jupiter. We conclude that the behaviour of our giant planets, characterized by substantial radial migration, is more similar to that inferred for extra-solar planets than previously thought.
The Astrophysical Journal, Jan 1, 2008
The Astrophysical …, Jan 1, 2008
The Astronomical …, Jan 1, 2007
The Astronomical …, Jan 1, 2007
The Astronomical …, Jan 1, 2007
Public reporting burden for the collection of information is estimated to average 1 hour per resp... more Public reporting burden for the collection of information is estimated to average 1 hour per response, including the time for reviewing instructions, searching existing data sources, gathering and maintaining the data needed, and completing and reviewing the collection of information. Send comments regarding this burden estimate or any other aspect of this collection of information, including suggestions for reducing this burden, to Washington Headquarters Services, Directorate for Information Operations and Reports, 1215 Jefferson Davis Highway, Suite 1204, Arlington VA 22202-4302. Respondents should be aware that notwithstanding any other provision of law, no person shall be subject to a penalty for failing to comply with a collection of information if it does not display a currently valid OMB control number.