Related papers: Initial Planetesimal Sizes and the Size Distributi…
Recent studies claimed that planets around the same star have similar sizes and masses and regular spacings, and that planet pairs usually show ordered sizes such that the outer planet is usually the larger one. Here I show that these…
We consider the size distribution of superbubbles in a star forming galaxy. Previous studies have tried to explain the distribution by using adiabatic self-similar evolution of wind driven bubbles, assuming that bubbles stall when pressure…
A critical step toward the emergence of planets in a protoplanetary disk consists in accretion of planetesimals, bodies 1-1000 km in size, from smaller disk constituents. This process is poorly understood partly because we lack good…
We analyze 40 cosmological re-simulations of individual massive galaxies with present-day stellar masses of $M_{*} > 6.3 \times 10^{10} M_{\odot}$ in order to investigate the physical origin of the observed strong increase in galaxy sizes…
By means of galaxy evolutionary models, we explore the direct consequences of the LCDM cosmogony on the size evolution of galactic discs, avoiding intentionally the introduction of intermediate (uncertain) astrophysical processes. Based on…
The dynamical interaction of minor bodies (such as comets or asteroids) with planets plays an essential role in the planetary system's architecture and evolution. As a result of these interactions, structures like the Kuiper belt and the…
We simulate the coupled stellar and tidal evolution of short-period binary stars (orbital period $P_{orb} \lsim$8 days) to investigate the orbital oscillations, instellation cycles, and orbital stability of circumbinary planets (CBPs). We…
The dust produced in the Kuiper Belt (KB) spreads throughout the Solar System forming a dust disk. We numerically model the orbital evolution of KB dust and estimate its equilibrium spatial distribution and its brightness and spectral…
The accretion of pebbles on planetary cores has been widely studied in recent years and is found to be a highly effective mechanism for planetary growth. While most studies assume planetary cores as an initial condition in their simulation,…
Here we show an example of a young asteroid cluster located in a dynamically stable region, which was produced by partial disruption of a primitive body about 30 km in size. We estimate its age to be only 1.9 +/- 0.3 Myr, thus its…
When planetesimals grow via collisions in a turbulent disk, stirring through density fluctuation caused by turbulence effectively increases the relative velocities between planetesimals, which suppresses the onset of runaway growth. We…
The Kepler mission has discovered about a dozen circumbinary planetary systems, all containing planets on ~ 1 AU orbits. We place bounds on the locations in the circumbinary protoplanetary disk, where these planets could have formed through…
Planetesimals in the primordial disc may have experienced a collisional cascade. If so, the comet nuclei later placed in the Kuiper belt, scattered disc, and Oort Cloud would primarily be fragments and collisional rubble piles from that…
We employ an efficient numerical approach to simulate a stationary distribution of test objects, which results from their gravitational scattering on the four giant planets, with accounting for effects of mean motion resonances. Using the…
Strong size and internal density evolution of early-type galaxies between z~2 and the present has been reported by several authors. Here we analyze samples of nearby and distant (z~1) galaxies with dynamically measured masses in order to…
[abridged] Massive, passively evolving galaxies at redshifts z>1 exhibit on the average physical sizes smaller by factors ~3 than local early type galaxies (ETGs) endowed with the same stellar mass. Small sizes are in fact expected on…
We consider constraints on the planetesimal population residing in the disks of AU Microscopii, Beta Pictoris and Fomalhaut taking into account their observed thicknesses and normal disk opacities. We estimate that bodies of radius 5, 180…
Many multiple-planet systems have been found by the Kepler transit survey and various radial velocity (RV) surveys. Kepler planets show an asymmetric feature, namely, there are small but significant deficits/excesses of planet pairs with…
Recent analyses have shown that distant orbits within the scattered disk population of the Kuiper belt exhibit an unexpected clustering in their respective arguments of perihelion. While several hypotheses have been put forward to explain…
We investigate classical planetesimal accretion in a binary star system of separation ab<50AU by numerical simulations, with particular focus on the region at a distance of 1 AU from the primary. The planetesimals orbit the primary, are…