The kinetic theory is used to study the evolution of the self-gravitating disk of planetesimals. The effects of frequent collisions between planetesimals are taken into account by using a Krook integral in the Boltzmann kinetic equation. It is shown that as a result of an aperiodic collision-dissipative instability of small gravity disturbances the disk is subdivided into numerous dense fragments. These can eventually condense into the planetary sequence.

In this paper we demonstrate how the action of secular resonances near the inner edge of the asteroid belt strongly effects the inclinations and eccentricities of asteroidal dust particles, such that they lose the orbital characteristics of their parent body and are dispersed into the zodiacal background. As a consequence, it may not be possible to relate the distribution of interplanetary material at 1 AU to given asteroidal or cometary sources with the level of confidence previously imagined.

For the plane motion we are completely analyzing the differential equations systems of gravitational capture of the exoplanet at the resonance rotation with action of gravitational and tidal torques by qualitative analysis and bifurcation theory of dynamical systems (DS). The separation of 3-dimensional parameter space of dynamical system by bifurcation surfaces is obtained. The gallery of more than thirty phase portraits of gravitational capture extends the known scenario of cosmogonical evolution of the exoplanet on the early time, when the tidal interaction is very important.

Migration of planetesimals and embryos of forming planets was investigated on the basis of computer runs of the evolution of disks of gravitating bodies orbiting the Sun. Our results obtained earlier with the use of the spheres' method are close to the results obtained recently by other authors by numerical integration. Due to the interaction with migrating planetesimals, the embryos of Uranus and Neptune, which acquired most of their masses near the orbit of Saturn, could migrate to the present distances from the Sun moving all time in nearly circular orbits. Each of the terrestrial planets incorporated planetesimals from all feeding zones of these planets.

Doppler observation of extrasolar planets through the radial velocity displacement of their host stars can only determine lower limits of planetary masses. We numerically integrate ν Andromedae planetary orbits with various initial conditions of masses and angle variables to investigate which initial configuration produces stable orbits during the timescale of host star's age. According to our preliminary results starting from Lick dataset, ν Andromedae planetary system seems to remain stable over the timescale of its host star's age if sin i > 0.7 where i is the unknown line-of-sight inclination of planetary orbits. In this case we may estimate that the upper limit masses of ν Andromedae planets in our model is about 1/0.7 ∽ 1.43 times larger than its minimum.

It has been suggested that circumstellar disks evolve from dense, actively accreting structures to low-mass, replenished remnants. During this transition, grains may assemble into planetesimals, or the disk may be cleared by newborn planets. Recently identified nearby groups of young stars provide valuable laboratories for probing disk evolution. I discuss the properties of dust disks in the TW Hydrae Association and the MBM 12 cloud, and compare the results to other studies of disk evolution and planet formation timescales.

We have investigated whether terrestrial planets can exist in orbits in known exoplanetary systems such that life could have emerged on those planets. We have shown that Rho CrB and 47 UMa could have terrestrial planets in orbits that remain confined to their habitable zones for biologically significant lengths of time. We have also shown that the Gliese 876 and Ups And systems are very unlikely to have such orbits.

Three planets are detected around ν Andromedae. The stability of Upsilon Andromedae Planetary system is maintained by the co rotation of the pericenters of the two outer planets. If the pericenters of the two outer planets move independently, the planetary system becomes unstable. The corotation of the pericenters is explained by the secular perturbation theory. This corotation is not a secular resonance.

We investigate the equation describing the evolution of the kinetic momentum vector for the case of non-resonance rotation of dynamically symmetrical planets by action of gravitational and magnetic interaction with the central star. The obtained gallery of more twenty phase portraits of kinetic momentum evolution illustrates the various regimes of the planetary systems evolution. The analyses of obtained portraits has shown that a direct rotation of the planet may be passed into reverse rotation and vice versa for a rather broad range of the parameters.

We present the latest results of large scale (N = 10000, 0.5AU < a < 1.5AU) N-body simulations of planetary accretion. We confirm the oligarchic growth of protoplanets in the minimum-mass disk and a more massive disk models. Protoplanets with the predicted isolation mass are formed with orbital separation of about 10-15 Hill radius.

We present new results related to the coupled evolution of a two giant planet system embedded in a protoplanetary disk, in which a Saturn mass protoplanet is trapped in an outer mean motion resonance with a Jupiter mass protoplanet. The gaps opened in the disk by the two planets overlap, therefore the two planet system exchanges angular momentum with the disk at the inner planet's Inner Lindblad Resonances (ILRs) and at the outer planet Outer Lindblad Resonances (OLRs). Since the torques are proportional to the square of the planet masses, and since the inner planet is about three times more massive than the outer one, the ILR torques are favored by a factor ∽ 10 with respect to the one planet case. In the case presented here, this leads to a positive differential Lindblad torque and consequently an outwards migration. We briefly discuss the long-term behavior of the system, which could account for the high eccentricities of the extra-solar planets with semimajor axis a > 0.2 AU.

We have previously given evidence based on Oort cloud comet orbital elements which suggested that there may be a Jovian-mass brown dwarf in our solar system. An extended cometary database is now available. The analyses have been repeated and we find that the set of statistically significant correlated anomalies is enhanced. We also respond to unsupported objections that have been raised to this conjecture. If real, the wide-binary object would constitute a natural dynamical intermediary between gas giant planetary objects and isolated objects.

We investigate the minimum mass of brown dwarfs using radiation hydrodynamics simulations of collapsing filamentary clouds and analytical estimates. We found the minimum mass of brown dwarfs depends on the initial temperature of parent clouds and the nature of heating sources. The universal minimum mass of brown dwarfs, which is about 0.007M⊙, is given when the initial cloud temperature is 13.3 K. Our results are consistent with recent observations of low-mass objects in some star forming regions.

Free oscillations of the earth received much attention by the pioneering work of Benioff (1954). He observed an oscillation period of 57 minutes by investigating the data of Kamchatka earthquake and assumed the free oscillations of the earth as its origin. Since then many aspects of the problem has been investigated by different authors.

I present a two dimensional hydrodynamic simulation of a binary system consisting of two stars, each with a circumstellar disk, using a Smoothed Particle Hydrodynamic (SPH) code. I model the luminous output of this system in various millimeter and sub-millimeter wavelength bands appropriate for several new and soon to be on line interferometric telescopes and find that spiral structure present in the density structure of the disks will be difficult or impossible to observe in the observed emission from the system, due to the fact that disk photosphere temperatures are not very sensitive to the underlying density distribution.

We present the results of 2–D non linear hydrodynamic simulations performed to examine the driving of orbital eccentricity through disc-companion tidal interaction. We examine the eccentricity evolution for companion masses, mp, in the range 1 > mp >; 30 MJupiter. The disc model we employ is similar to a minimum mass solar nebula model.

We find that there is a transition in behaviour, characterised by a rapid growth in eccentricity, for companion masses mp ≳ 20 MJupiter. Companions with masses below this limit show essentially no growth in eccentricity, for the disc model parameters that we examine. Our results suggest that if giant planets form from protostellar discs with properties similar to those studied in this paper, then the observed orbital eccentricities of the extrasolar planets are not a consequence of tidal interaction with their protostellar discs during formation.

We have obtained viscous stirring and dynamical friction rates of planetesimals based on three-body orbital integrations, taking into account the Rayleigh distribution of eccentricities and inclinations. We have found that the evolution of root mean square eccentricities and inclinations calculated by using these rates agrees with N-body simulations quite well.

An eccentric protoplanetary gaseous disc provides a slowly precessing non axisymmetric mass distribution. As a result of self-gravity, the precession frequency may resonate with that of a near circular protoplanet orbit within an inner cavity. A large eccentricity might then be produced.

Frequency Map Analysis (FMA) (Laskar, 1990, 1999) is a refined numerical method based on Fourier techniques which provide a clear representation of the global dynamics of multi-dimensional systems, which is very effective for systems of 3 degrees of freedom and more, and was applied to a large class of dynamical systems. FMA requires only a very short integration time to obtain a measure of the diffusion of the trajectories, and allows to identify easily the location of the main resonances. Using this method, we have performed a complete analysis of massless particles in the Solar System (Robutel & Laskar 2001), from Mercury to the outer parts of the Kuiper belt (90 AU), for all values of the eccentricities, and several values for the inclinations. This provides a complete dynamical map of the Solar System, which is, in this first step, restricted to mean motion resonances. The dynamics of a planetary system which all the bodies have no zero mass can be studied with the same methods: an application to the JupiterSaturn system can be fined in (Robutel & Laskar 2002). We present here the application of this method to the understanding of the dynamics of the newly discovered v-Andromedae system.

Ensembles of in-plane and inclined orbits in the vicinity of the Lagrange points of the terrestrial planets are integrated for up to 100 million years. Mercurian Trojans probably do not exist, although there is evidence for long-lived, corotating horseshoe orbits with small inclinations. Both Venus and the Earth are much more promising, as they possess rich families of stable tadpole and horseshoe orbits. Our survey of in-plane test particles near the Martian Lagrange points shows no survivors after 60 million years. Low inclination test particles do not persist, as their inclinations are quickly increased until the effects of a secular resonance with Jupiter cause de-stabilisation. Numerical integrations of inclined test particles for timespans of 25 million years show stable zones for inclinations between 14° and 40°. Both Martian Trojans 5261 Eureka and 1998 VF31 lie deep within the stable zones, which suggests they may be of primordial origin.