184 research outputs found
Terrestrial-type planet formation: Comparing different types of initial conditions
To study the terrestrial-type planet formation during the post oligarchic
growth, the initial distributions of planetary embryos and planetesimals used
in N-body simulations play an important role. Most of these studies typically
use ad hoc initial distributions based on theoretical and numerical studies. We
analyze the formation of planetary systems without gas giants around solar-type
stars focusing on the sensitivity of the results to the particular initial
distributions of planetesimals and embryos. The formation of terrestrial
planets in the habitable zone (HZ) and their final water contents are topics of
interest. We developed two different sets of N-body simulations from the same
protoplanetary disk. The first set assumes ad hoc initial distributions for
embryos and planetesimals and the second set obtains these distributions from
the results of a semi-analytical model which simulates the evolution of the
gaseous phase of the disk. Both sets form planets in the HZ. Ad hoc initial
conditions form planets in the HZ with masses from to
. More realistic initial conditions obtained from a
semi-analytical model, form planets with masses between and
. Both sets form planets in the HZ with water contents between
4.5% and 39.48% by mass. Those planets with the highest water contents respect
to those with the lowest, present differences regarding the sources of water
supply. We suggest that the number of planets in the HZ is not sensitive to the
particular initial distribution of embryos and planetesimals and thus, the
results are globally similar between both sets. However, the main differences
are associated to the accretion history of the planets in the HZ. These
discrepancies have a direct impact in the accretion of water-rich material and
in the physical characteristics of the resulting planets.Comment: Accepted for publication in Astronomy and Astrophysics, 13 pages, 9
figure
Extracting topological features from dynamical measures in networks of Kuramoto oscillators
The Kuramoto model for an ensemble of coupled oscillators provides a
paradigmatic example of non-equilibrium transitions between an incoherent and a
synchronized state. Here we analyze populations of almost identical oscillators
in arbitrary interaction networks. Our aim is to extract topological features
of the connectivity pattern from purely dynamical measures, based on the fact
that in a heterogeneous network the global dynamics is not only affected by the
distribution of the natural frequencies, but also by the location of the
different values. In order to perform a quantitative study we focused on a very
simple frequency distribution considering that all the frequencies are equal
but one, that of the pacemaker node. We then analyze the dynamical behavior of
the system at the transition point and slightly above it, as well as very far
from the critical point, when it is in a highly incoherent state. The gathered
topological information ranges from local features, such as the single node
connectivity, to the hierarchical structure of functional clusters, and even to
the entire adjacency matrix.Comment: 11 pages, 10 figure
Chemical composition of Earth-like planets
Models of planet formation are mainly focused on the accretion and dynamical
processes of the planets, neglecting their chemical composition. In this work,
we calculate the condensation sequence of the different chemical elements for a
low-mass protoplanetary disk around a solar-type star. We incorporate this
sequence of chemical elements (refractory and volatile elements) in our
semi-analytical model of planet formation which calculates the formation of a
planetary system during its gaseous phase. The results of the semi-analytical
model (final distributions of embryos and planetesimals) are used as initial
conditions to develope N-body simulations that compute the post-oligarchic
formation of terrestrial-type planets. The results of our simulations show that
the chemical composition of the planets that remain in the habitable zone has
similar characteristics to the chemical composition of the Earth. However,
exist differences that can be associated to the dynamical environment in which
they were formed.Comment: 3 pages, 4 figures - Accepted for publication in the Bolet\'in de la
Asociaci\'on Argentina de Astronom\'ia, vol.5
Effects of an eccentric inner Jupiter on the dynamical evolution of icy body reservoirs in a planetary scattering scenario
Aims. We analyze the dynamics of small body reservoirs under the effects of an eccentric inner giant planet resulting from a planetary scattering event around a 0.5 M⊙ star. Methods. First, we used a semi-analytical model to define the properties of the protoplanetary disk that lead to the formation of three Jupiter-mass planets. Then, we carried out N-body simulations assuming that the planets are close to their stability limit together with an outer planetesimal disk. In particular, the present work focused on the analysis of N-body simulations in which a single Jupiter-mass planet survives after the dynamical instability event. Results. Our simulations produce outer small body reservoirs with particles on prograde and retrograde orbits, and other ones whose orbital plane flips from prograde to retrograde and back again along their evolution (“Type-F particles”). We find strong correlations between the inclination i and the ascending node longitude Ω of Type-F particles. First, Ω librates around 90° or/and 270°. This property represents a necessary and sufficient condition for the flipping of an orbit. Moreover, the libration periods of i and Ω are equal and they are out to phase by a quarter period. We also remark that the larger the libration amplitude of i, the larger the libration amplitude of Ω. We analyze the orbital parameters of Type-F particles immediately after the instability event (post IE orbital parameters), when a single Jupiter-mass planet survives in the system. Our results suggest that the orbit of a particle can flip for any value of its post IE eccentricity, although we find only two Type-F particles with post IE inclinations i ≲ 17°. Finally, our study indicates that the minimum value of the inclination of the Type-F particles in a given system decreases with an increase in the eccentricity of the giant planet.Fil: Zanardi, Macarena. Universidad Nacional de La Plata. Facultad de Ciencias AstronĂłmicas y GeofĂsicas; Argentina. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Centro CientĂfico TecnolĂłgico Conicet - La Plata. Instituto de AstrofĂsica La Plata. Universidad Nacional de La Plata. Facultad de Ciencias AstronĂłmicas y GeofĂsicas. Instituto de AstrofĂsica La Plata; ArgentinaFil: de Elia, Gonzalo Carlos. Universidad Nacional de La Plata. Facultad de Ciencias AstronĂłmicas y GeofĂsicas; Argentina. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Centro CientĂfico TecnolĂłgico Conicet - La Plata. Instituto de AstrofĂsica La Plata. Universidad Nacional de La Plata. Facultad de Ciencias AstronĂłmicas y GeofĂsicas. Instituto de AstrofĂsica La Plata; ArgentinaFil: Di Sisto, Romina Paula. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Centro CientĂfico TecnolĂłgico Conicet - La Plata. Instituto de AstrofĂsica La Plata. Universidad Nacional de La Plata. Facultad de Ciencias AstronĂłmicas y GeofĂsicas. Instituto de AstrofĂsica La Plata; Argentina. Universidad Nacional de La Plata. Facultad de Ciencias AstronĂłmicas y GeofĂsicas; ArgentinaFil: Naoz, S.. University of California at Los Angeles; Estados UnidosFil: Li, G.. Harvard-Smithsonian Center for Astrophysics; Estados UnidosFil: Guilera, O. M.. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Centro CientĂfico TecnolĂłgico Conicet - La Plata. Instituto de AstrofĂsica La Plata. Universidad Nacional de La Plata. Facultad de Ciencias AstronĂłmicas y GeofĂsicas. Instituto de AstrofĂsica La Plata; Argentina. Universidad Nacional de La Plata. Facultad de Ciencias AstronĂłmicas y GeofĂsicas; ArgentinaFil: Brunini, A.. Universidad Nacional de la Patagonia Austral; Argentin
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