Sean Raymond | Centre National de la Recherche Scientifique / French National Centre for Scientific Research (original) (raw)

Papers by Sean Raymond

Jupiter and Saturn formed in a few million years (ref. 1) from a gas-dominated protoplanetary dis... more Jupiter and Saturn formed in a few million years (ref. 1) from a gas-dominated protoplanetary disk, and were susceptible to gas-driven migration of their orbits on timescales of only~ 100,000 years (ref. 2). Hydrodynamic simulations show that these giant planets can undergo a two-stage, inward-then-outward, migration 3, 4, 5.

ABSTRACT Most of the first-discovered extrasolar multiplanet systems were found to lie close to d... more ABSTRACT Most of the first-discovered extrasolar multiplanet systems were found to lie close to dynamically unstable configurations. However, a few observed multiplanet systems (eg, HD 74156) did not show this trait. Those systems could share this property if they contain an additional planet in between those that are known. Previous investigations identified the properties of hypothetical planets that would place these systems near instability.

ABSTRACT We study the final architecture of planetary systems that evolve under the combined effe... more ABSTRACT We study the final architecture of planetary systems that evolve under the combined effects of planet-planet and planetesimal scattering. Using N-body simulations we investigate the dynamics of marginally unstable systems of gas and ice giants both in isolation and when the planets form interior to a planetesimal belt. The unstable isolated systems evolve under planet-planet scattering to yield an eccentricity distribution that matches that observed for extrasolar planets.

ABSTRACT Five planets are known to orbit the star 55 Cancri. The recently discovered planet f at ... more ABSTRACT Five planets are known to orbit the star 55 Cancri. The recently discovered planet f at 0.78 AU (Fischer et al.) is located at the inner edge of a previously identified stable zone that separates the three close-in planets from planet d at 5.9 AU. Here we map the stability of the orbital space between planets f and d using a suite of n-body integrations that include an additional, yet-to-be-discovered planet g with a radial velocity amplitude of 5 ms–1 (planet\ mathrm {mass}\,= 0.5 {\ mbox {--}} 1.2 Saturn masses).

Abstract Context. It has recently been shown that the terrestrial planets and asteroid belt can b... more Abstract Context. It has recently been shown that the terrestrial planets and asteroid belt can be reproduced if the giant planets underwent an inward-then-outward migration (the “Grand Tack”; Walsh and collaborators). Inward migration occurs when Jupiter opens a gap and type II migrates inward. The planets “tack” and migrate outward when Saturn reaches the gap-opening mass and is caught in the 3: 2 resonance with Jupiter. Aims.

Abstract: Given the very close proximity of their habitable zones, brown dwarfs represent high-va... more Abstract: Given the very close proximity of their habitable zones, brown dwarfs represent high-value targets in the search for nearby transiting habitable planets that may be suitable for follow-up occultation spectroscopy. In this paper we develop search strategies to find habitable planets transiting brown dwarfs depending on their maximum habitable orbital period (PHZ out).

Abstract: The first full year of operation following the commissioning year of the Sloan Digital ... more Abstract: The first full year of operation following the commissioning year of the Sloan Digital Sky Survey has revealed a wide variety of newly discovered cataclysmic variables. We show the SDSS spectra of forty-two cataclysmic variables observed in 2002, of which thirty-five are new classifications, four are known dwarf novae (CT Hya, RZ Leo, T Leo and BZ UMa), one is a known CV identified from a previous quasar survey (Aqr1) and two are known ROSAT or FIRST discovered CVs (RX J09445+ 0357, FIRST J102347. 6+ 003841).

Abstract:Hot jupiters,'giant planets with orbits very close to their parent stars, are thought to... more Abstract: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 (Armitage 2003). We present results of simulations of terrestrial planet formation in the presence of hot jupiters, broadly defined as having orbital radii<= 0.5 AU.

Abstract: Tides may be crucial to the habitability of exoplanets. If such planets form around low... more Abstract: Tides may be crucial to the habitability of exoplanets. If such planets form around low-mass stars, then those in the circumstellar habitable zone will be close enough to their host stars to experience strong tidal forces. Tides may result in orbital decay and circularization, evolution toward zero obliquity, a fixed rotation rate (not necessarily synchronous), and substantial internal heating.

Abstract The eccentric orbits of the known extrasolar giant planets provide evidence that most pl... more Abstract The eccentric orbits of the known extrasolar giant planets provide evidence that most planet-forming environments undergo violent dynamical instabilities. Here, we numerically simulate the impact of giant planet instabilities on planetary systems as a whole. We find that populations of inner rocky and outer icy bodies are both shaped by the giant planet dynamics and are naturally correlated. Strong instabilities–those with very eccentric surviving giant planets–completely clear out their inner and outer regions.

Abstract: In this chapter we review the astrophysical origins of Earth's carbon, starting from th... more Abstract: In this chapter we review the astrophysical origins of Earth's carbon, starting from the products of the Big Bang and culminating with the Earth's formation. We review the measured compositions of different primitive objects including comets, various classes of meteorites and interstellar dust particles. We discuss the composition of the Solar Nebula, especially with regards to the distribution of volatiles such as carbon.

Nearly half the exoplanets found within binary star systems reside 1 in very wide binaries with a... more Nearly half the exoplanets found within binary star systems reside 1 in very wide binaries with average stellar separations greater than 1,000 astronomical units (one astronomical unit (au) being the Earth–Sun distance), yet the influence of such distant binary companions on planetary evolution remains largely unstudied. Unlike their tighter counterparts, the stellar orbits of wide binaries continually change under the influence of the Milky Way's tidal field and impulses from other passing stars.

Abstract: One of the most surprising discoveries of extrasolar planets is the detection of planet... more Abstract: One of the most surprising discoveries of extrasolar planets is the detection of planets in moderately close binary star systems. The Jovian-type planets in the two binaries of Gamma Cephei and GJ 86 have brought to the forefront questions on the formation of giant planets and the possibility of the existence of smaller bodies in such dynamically complex environments.

Abstract: We review how tides may impact the habitability of terrestrial-like planets. If such pl... more Abstract: We review how tides may impact the habitability of terrestrial-like planets. If such planets form around low-mass stars, then planets in the circumstellar habitable zone will be close enough to their host stars to experience strong tidal forces. We discuss 1) decay of semi-major axis, 2) circularization of eccentric orbits, 3) evolution toward zero obliquity, 4) fixed rotation rates (not necessarily synchronous), and 5) internal heating.

Abstract: Prior work has found that a variety of terrestrial planetary compositions are expected ... more Abstract: Prior work has found that a variety of terrestrial planetary compositions are expected to occur within known extrasolar planetary systems. However, such studies ignored the effects of giant planet migration, which is thought to be very common in extra-solar systems. Here we present calculations of the compositions of terrestrial planets that formed in dynamical simulations incorporating varying degrees of giant planet migration.

Abstract Context. The spin rate of stars evolves substantially during their lifetime, owing to th... more Abstract Context. The spin rate of stars evolves substantially during their lifetime, owing to the evolution of their internal structure and to external torques arising from the interaction of stars with their environments and stellar winds. Aims. We investigate how the evolution of the stellar spin rate affects, and is affected by, planets in close orbits via star-planet tidal interactions. Methods.

Abstract. Terrestrial planets form in a series of dynamical steps from the solid component of cir... more Abstract. Terrestrial planets form in a series of dynamical steps from the solid component of circumstellar disks. First, km-sized planetesimals form likely via a combination of sticky collisions, turbulent concentration of solids, and gravitational collapse from micron-sized dust grains in the thin disk midplane. Second, planetesimals coalesce to form Moon-to Mars-sized protoplanets, also called “planetary embryos”. Finally, full-sized terrestrial planets accrete from protoplanets and planetesimals.

Abstract A complete census of planetary systems around a volume-limited sample of solar-type star... more Abstract A complete census of planetary systems around a volume-limited sample of solar-type stars (FGK dwarfs) in the Solar neighborhood (d≤ 15 pc) with uniform sensitivity down to Earth-mass planets within their Habitable Zones out to several AUs would be a major milestone in extrasolar planets astrophysics. This fundamental goal can be achieved with a mission concept such as NEAT—the Nearby Earth Astrometric Telescope.

ABSTRACT Although the 55 Cnc system contains multiple, closely packed planets that are presumably... more ABSTRACT Although the 55 Cnc system contains multiple, closely packed planets that are presumably in a coplanar configuration, we use numerical simulations to demonstrate that they are likely to be highly inclined to their parent star's spin axis. Due to perturbations from its distant binary companion, this planetary system precesses like a rigid body about its parent star. Consequently, the parent star's spin axis and the planetary orbit normal likely diverged long ago.

Abstract: This paper reviews our current understanding of terrestrial planets formation. The focu... more Abstract: 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.

Jupiter and Saturn formed in a few million years (ref. 1) from a gas-dominated protoplanetary dis... more Jupiter and Saturn formed in a few million years (ref. 1) from a gas-dominated protoplanetary disk, and were susceptible to gas-driven migration of their orbits on timescales of only~ 100,000 years (ref. 2). Hydrodynamic simulations show that these giant planets can undergo a two-stage, inward-then-outward, migration 3, 4, 5.

ABSTRACT Most of the first-discovered extrasolar multiplanet systems were found to lie close to d... more ABSTRACT Most of the first-discovered extrasolar multiplanet systems were found to lie close to dynamically unstable configurations. However, a few observed multiplanet systems (eg, HD 74156) did not show this trait. Those systems could share this property if they contain an additional planet in between those that are known. Previous investigations identified the properties of hypothetical planets that would place these systems near instability.

ABSTRACT We study the final architecture of planetary systems that evolve under the combined effe... more ABSTRACT We study the final architecture of planetary systems that evolve under the combined effects of planet-planet and planetesimal scattering. Using N-body simulations we investigate the dynamics of marginally unstable systems of gas and ice giants both in isolation and when the planets form interior to a planetesimal belt. The unstable isolated systems evolve under planet-planet scattering to yield an eccentricity distribution that matches that observed for extrasolar planets.

ABSTRACT Five planets are known to orbit the star 55 Cancri. The recently discovered planet f at ... more ABSTRACT Five planets are known to orbit the star 55 Cancri. The recently discovered planet f at 0.78 AU (Fischer et al.) is located at the inner edge of a previously identified stable zone that separates the three close-in planets from planet d at 5.9 AU. Here we map the stability of the orbital space between planets f and d using a suite of n-body integrations that include an additional, yet-to-be-discovered planet g with a radial velocity amplitude of 5 ms–1 (planet\ mathrm {mass}\,= 0.5 {\ mbox {--}} 1.2 Saturn masses).

Abstract Context. It has recently been shown that the terrestrial planets and asteroid belt can b... more Abstract Context. It has recently been shown that the terrestrial planets and asteroid belt can be reproduced if the giant planets underwent an inward-then-outward migration (the “Grand Tack”; Walsh and collaborators). Inward migration occurs when Jupiter opens a gap and type II migrates inward. The planets “tack” and migrate outward when Saturn reaches the gap-opening mass and is caught in the 3: 2 resonance with Jupiter. Aims.

Abstract: Given the very close proximity of their habitable zones, brown dwarfs represent high-va... more Abstract: Given the very close proximity of their habitable zones, brown dwarfs represent high-value targets in the search for nearby transiting habitable planets that may be suitable for follow-up occultation spectroscopy. In this paper we develop search strategies to find habitable planets transiting brown dwarfs depending on their maximum habitable orbital period (PHZ out).

Abstract: The first full year of operation following the commissioning year of the Sloan Digital ... more Abstract: The first full year of operation following the commissioning year of the Sloan Digital Sky Survey has revealed a wide variety of newly discovered cataclysmic variables. We show the SDSS spectra of forty-two cataclysmic variables observed in 2002, of which thirty-five are new classifications, four are known dwarf novae (CT Hya, RZ Leo, T Leo and BZ UMa), one is a known CV identified from a previous quasar survey (Aqr1) and two are known ROSAT or FIRST discovered CVs (RX J09445+ 0357, FIRST J102347. 6+ 003841).

Abstract:Hot jupiters,'giant planets with orbits very close to their parent stars, are thought to... more Abstract: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 (Armitage 2003). We present results of simulations of terrestrial planet formation in the presence of hot jupiters, broadly defined as having orbital radii<= 0.5 AU.

Abstract: Tides may be crucial to the habitability of exoplanets. If such planets form around low... more Abstract: Tides may be crucial to the habitability of exoplanets. If such planets form around low-mass stars, then those in the circumstellar habitable zone will be close enough to their host stars to experience strong tidal forces. Tides may result in orbital decay and circularization, evolution toward zero obliquity, a fixed rotation rate (not necessarily synchronous), and substantial internal heating.

Abstract The eccentric orbits of the known extrasolar giant planets provide evidence that most pl... more Abstract The eccentric orbits of the known extrasolar giant planets provide evidence that most planet-forming environments undergo violent dynamical instabilities. Here, we numerically simulate the impact of giant planet instabilities on planetary systems as a whole. We find that populations of inner rocky and outer icy bodies are both shaped by the giant planet dynamics and are naturally correlated. Strong instabilities–those with very eccentric surviving giant planets–completely clear out their inner and outer regions.

Abstract: In this chapter we review the astrophysical origins of Earth's carbon, starting from th... more Abstract: In this chapter we review the astrophysical origins of Earth's carbon, starting from the products of the Big Bang and culminating with the Earth's formation. We review the measured compositions of different primitive objects including comets, various classes of meteorites and interstellar dust particles. We discuss the composition of the Solar Nebula, especially with regards to the distribution of volatiles such as carbon.

Nearly half the exoplanets found within binary star systems reside 1 in very wide binaries with a... more Nearly half the exoplanets found within binary star systems reside 1 in very wide binaries with average stellar separations greater than 1,000 astronomical units (one astronomical unit (au) being the Earth–Sun distance), yet the influence of such distant binary companions on planetary evolution remains largely unstudied. Unlike their tighter counterparts, the stellar orbits of wide binaries continually change under the influence of the Milky Way's tidal field and impulses from other passing stars.

Abstract: One of the most surprising discoveries of extrasolar planets is the detection of planet... more Abstract: One of the most surprising discoveries of extrasolar planets is the detection of planets in moderately close binary star systems. The Jovian-type planets in the two binaries of Gamma Cephei and GJ 86 have brought to the forefront questions on the formation of giant planets and the possibility of the existence of smaller bodies in such dynamically complex environments.

Abstract: We review how tides may impact the habitability of terrestrial-like planets. If such pl... more Abstract: We review how tides may impact the habitability of terrestrial-like planets. If such planets form around low-mass stars, then planets in the circumstellar habitable zone will be close enough to their host stars to experience strong tidal forces. We discuss 1) decay of semi-major axis, 2) circularization of eccentric orbits, 3) evolution toward zero obliquity, 4) fixed rotation rates (not necessarily synchronous), and 5) internal heating.

Abstract: Prior work has found that a variety of terrestrial planetary compositions are expected ... more Abstract: Prior work has found that a variety of terrestrial planetary compositions are expected to occur within known extrasolar planetary systems. However, such studies ignored the effects of giant planet migration, which is thought to be very common in extra-solar systems. Here we present calculations of the compositions of terrestrial planets that formed in dynamical simulations incorporating varying degrees of giant planet migration.

Abstract Context. The spin rate of stars evolves substantially during their lifetime, owing to th... more Abstract Context. The spin rate of stars evolves substantially during their lifetime, owing to the evolution of their internal structure and to external torques arising from the interaction of stars with their environments and stellar winds. Aims. We investigate how the evolution of the stellar spin rate affects, and is affected by, planets in close orbits via star-planet tidal interactions. Methods.

Abstract. Terrestrial planets form in a series of dynamical steps from the solid component of cir... more Abstract. Terrestrial planets form in a series of dynamical steps from the solid component of circumstellar disks. First, km-sized planetesimals form likely via a combination of sticky collisions, turbulent concentration of solids, and gravitational collapse from micron-sized dust grains in the thin disk midplane. Second, planetesimals coalesce to form Moon-to Mars-sized protoplanets, also called “planetary embryos”. Finally, full-sized terrestrial planets accrete from protoplanets and planetesimals.

Abstract A complete census of planetary systems around a volume-limited sample of solar-type star... more Abstract A complete census of planetary systems around a volume-limited sample of solar-type stars (FGK dwarfs) in the Solar neighborhood (d≤ 15 pc) with uniform sensitivity down to Earth-mass planets within their Habitable Zones out to several AUs would be a major milestone in extrasolar planets astrophysics. This fundamental goal can be achieved with a mission concept such as NEAT—the Nearby Earth Astrometric Telescope.

ABSTRACT Although the 55 Cnc system contains multiple, closely packed planets that are presumably... more ABSTRACT Although the 55 Cnc system contains multiple, closely packed planets that are presumably in a coplanar configuration, we use numerical simulations to demonstrate that they are likely to be highly inclined to their parent star's spin axis. Due to perturbations from its distant binary companion, this planetary system precesses like a rigid body about its parent star. Consequently, the parent star's spin axis and the planetary orbit normal likely diverged long ago.

Abstract: This paper reviews our current understanding of terrestrial planets formation. The focu... more Abstract: 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.