Trapping of giant-planet cores - I. Vortex aided trapping at the outer dead zone edge

In this paper the migration of a 10 Earth-mass planetary core is investigated at the outer boundary of the dead zone of a protoplanetary disc by means of 2D hydrodynamic simulations done with the graphics processor unit version of the FARGO code. In the dead zone, the effective viscosity is greatly reduced due to the disc self-shielding against stellar UV radiation, X-rays from the stellar magnetosphere and interstellar cosmic rays. As a consequence, mass accumulation occurs near the outer dead zone edge, which is assumed to trap planetary cores enhancing the efficiency of the core-accretion scenario to form giant planets. Contrary to the perfect trapping of planetary cores in 1D models, our 2D numerical simulations show that the trapping effect is greatly dependent on the width of the region where viscosity reduction is taking place. Planet trapping happens exclusively if the viscosity reduction is sharp enough to allow the development of large-scale vortices due to the Rossby wave instability. The trapping is only temporarily, and its duration is inversely proportional to the width of the viscosity transition. However, if the Rossby wave instability is not excited, a ring-like axisymmetric density jump forms, which cannot trap the 10 Earth-mass planetary cores. We revealed that the stellar torque exerted on the planet plays an important role in the migration history as the barycentre of the system significantly shifts away from the star due to highly non-axisymmetric density distribution of the disc. Our results still support the idea of planet formation at density/pressure maximum, since the migration of cores is considerably slowed down enabling them further growth and runaway gas accretion in the vicinity of an overdense region.Comment: 23 pages, 31 figures, accepted for publication in MNRA

On the dynamics of Extrasolar Planetary Systems under dissipation. Migration of planets

We study the dynamics of planetary systems with two planets moving in the same plane, when frictional forces act on the two planets, in addition to the gravitational forces. The model of the general three-body problem is used. Different laws of friction are considered. The topology of the phase space is essential in understanding the evolution of the system. The topology is determined by the families of stable and unstable periodic orbits, both symmetric and non symmetric. It is along the stable families, or close to them, that the planets migrate when dissipative forces act. At the critical points where the stability along the family changes, there is a bifurcation of a new family of stable periodic orbits and the migration process changes route and follows the new stable family up to large eccentricities or to a chaotic region. We consider both resonant and non resonant planetary systems. The 2/1, 3/1 and 3/2 resonances are studied. The migration to larger or smaller eccentricities depends on the particular law of friction. Also, in some cases the semimajor axes increase and in other cases they are stabilized. For particular laws of friction and for special values of the parameters of the frictional forces, it is possible to have partially stationary solutions, where the eccentricities and the semimajor axes are fixed.Comment: Accepted in Celestial Mechanics and Dynamical Astronom

An Earth with Two Suns

International audienceGravitational interactions between celestial bodies play an important role in multi-planetary systems as well as in binary stars hosting planets. Phenomena like mean motion resonances (MMR) or secular resonances can be sources of both stability and instability and influence therefore the architecture of a planetary system significantly. Intensive studies of the formation and evolution of planetary systems including our Solar system suggest that planets may not form in their final configuration. Responsible for changes in the orbital structure are processes like planetary migration, planet-planet scattering, mutual collisions and hyperbolic ejections which might occur after the gas disk disappears. The duration and the strength of this instability phase can determine whether a planetary system provides an appropriate environment for a habitable planet or not. Since the only habitable planet we know so far is our Earth, perhaps we should be looking for configurations that resemble our solar system? Finding an exact copy of the solar system is unlikely, however. Given the large percentage of binary and multiple star systems in the solar neighborhood, we investigate other possible configurations that share some dynamical characteristics with the solar system and ask where other terrestrial planets could provide conditions suitable for life

An Earth with Two Suns

International audienceGravitational interactions between celestial bodies play an important role in multi-planetary systems as well as in binary stars hosting planets. Phenomena like mean motion resonances (MMR) or secular resonances can be sources of both stability and instability and influence therefore the architecture of a planetary system significantly. Intensive studies of the formation and evolution of planetary systems including our Solar system suggest that planets may not form in their final configuration. Responsible for changes in the orbital structure are processes like planetary migration, planet-planet scattering, mutual collisions and hyperbolic ejections which might occur after the gas disk disappears. The duration and the strength of this instability phase can determine whether a planetary system provides an appropriate environment for a habitable planet or not. Since the only habitable planet we know so far is our Earth, perhaps we should be looking for configurations that resemble our solar system? Finding an exact copy of the solar system is unlikely, however. Given the large percentage of binary and multiple star systems in the solar neighborhood, we investigate other possible configurations that share some dynamical characteristics with the solar system and ask where other terrestrial planets could provide conditions suitable for life

An Earth with Two Suns

International audienceGravitational interactions between celestial bodies play an important role in multi-planetary systems as well as in binary stars hosting planets. Phenomena like mean motion resonances (MMR) or secular resonances can be sources of both stability and instability and influence therefore the architecture of a planetary system significantly. Intensive studies of the formation and evolution of planetary systems including our Solar system suggest that planets may not form in their final configuration. Responsible for changes in the orbital structure are processes like planetary migration, planet-planet scattering, mutual collisions and hyperbolic ejections which might occur after the gas disk disappears. The duration and the strength of this instability phase can determine whether a planetary system provides an appropriate environment for a habitable planet or not. Since the only habitable planet we know so far is our Earth, perhaps we should be looking for configurations that resemble our solar system? Finding an exact copy of the solar system is unlikely, however. Given the large percentage of binary and multiple star systems in the solar neighborhood, we investigate other possible configurations that share some dynamical characteristics with the solar system and ask where other terrestrial planets could provide conditions suitable for life

An Earth with Two Suns

International audienceGravitational interactions between celestial bodies play an important role in multi-planetary systems as well as in binary stars hosting planets. Phenomena like mean motion resonances (MMR) or secular resonances can be sources of both stability and instability and influence therefore the architecture of a planetary system significantly. Intensive studies of the formation and evolution of planetary systems including our Solar system suggest that planets may not form in their final configuration. Responsible for changes in the orbital structure are processes like planetary migration, planet-planet scattering, mutual collisions and hyperbolic ejections which might occur after the gas disk disappears. The duration and the strength of this instability phase can determine whether a planetary system provides an appropriate environment for a habitable planet or not. Since the only habitable planet we know so far is our Earth, perhaps we should be looking for configurations that resemble our solar system? Finding an exact copy of the solar system is unlikely, however. Given the large percentage of binary and multiple star systems in the solar neighborhood, we investigate other possible configurations that share some dynamical characteristics with the solar system and ask where other terrestrial planets could provide conditions suitable for life

Sensory and chemical freshness of rainbow trout (Oncorhynchus mykiss),gilthead sea bream (Sparus aurata), and carp (Cyprinus carpio) as affected by dietary fishmeal / fish oil replacement

International audienc

Impact of diets containing plant raw materials as fish meal and fish oil replacement on rainbow trout (Oncorhynchus mykiss), gilthead sea bream (Sparus aurata), and common carp (Cyprinus carpio) freshness

The present study aimed to evaluate whether the total or high substitution of fish meal (FM) and fish oil (FO) by sustainable plant raw materials (plant meal and oils) in long-term feeding for rainbow trout, gilthead sea bream, and common carp can result in spoilage alterations during ice storage. These three species were fed throughout their whole rearing cycle with plant-based diets and compared to counterparts that received FM/FO-based diets or commercial-like diets. Sensory QIM schemes adopted for these species and ATP breakdown products ( 835 c3e-value and components) were used to evaluate the freshness. Sensory acceptability of 14, 15, and 12 days was found for rainbow trout, gilthead sea bream, and common carp, respectively. This corresponded to 835 c3e-values of approximately 80%, 35%, and 65% for rainbow trout, gilthead sea bream, and common carp, respectively. No major effect of dietary history on postmortem shelf life was shown for gilthead sea bream and common carp; neither sensory-perceived nor chemical freshness showed diet-related differences. Rainbow trout fed with the plant-based diet exhibited slightly worse sensory freshness than fish fed with FM/FO-based diets, at the end of shelf life.These findings imply that FM and FO can be successfully substituted without major impacts on shelf life of fish