Related papers: A new condition for the transition from runaway to…
(abridged) When preplanetary bodies reach proportions of ~1 km or larger in size, their accretion rate is enhanced due to gravitational focusing (GF). We have developed a new numerical model to calculate the collisional evolution of the…
Runway growth is an important stage in planet formation during which large protoplanets form, while most of the initial mass remains in small planetesimals. The amount of mass converted into large protoplanets and their resulting size…
Runaway growth ends when the largest protoplanets dominate the dynamics of the planetesimal disk; the subsequent self-limiting accretion mode is referred to as ``oligarchic growth.'' Here, we begin by expanding on the existing analytic…
When planetesimals begin to grow by coagulation, they enter an epoch of runaway, during which the biggest bodies grow faster than all the others. The questions of how runaway ends and what comes next have not been answered satisfactorily.…
We describe planetesimal accretion calculations in the Kuiper Belt. Our evolution code simulates planetesimal growth in a single annulus and includes velocity evolution but not fragmentation. Test results match analytic solutions and…
We show, by comparing observations with theoretical models, that the observed Kuiper Belt size distribution is well matched by coagulation models, which start from an initial planetesimal population with radii of about 1km, and subsequent…
We consider the growth of a protoplanetary embryo embedded in a planetesimal disk. We take into account the dynamical evolution of the disk caused by (1) planetesimal-planetesimal interactions, which increase random motions and smooth…
We investigate planetary accretion that starts from equal-mass planetesimals using an analytic theory and numerical simulations. We particularly focus on how the planetary mass $M_{\rm oli}$ at the onset of oligarchic growth depends on the…
A critical phase in the standard model for planet formation is the runaway growth phase. During runaway growth bodies in the 0.1--100 km size range (planetesimals) quickly produce a number of much larger seeds. The runaway growth phase is…
This paper presents the results of collisional evolution calculations for the Kuiper belt starting from an initial size distribution similar to that produced by accretion simulations of that region - a steep power-law large object size…
We present a systematic examination of the changes in semi-major axis caused by the mutual interactions of a group of massive bodies orbiting a central star in the presence of eccentricity dissipation. For parameters relevant to the…
We study the stochastic coagulation equation using simplified models and efficient Monte Carlo simulations. It is known that (i) runaway growth occurs if the two-body coalescence kernel rises faster than linearly in the mass of the heavier…
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…
We study the efficiency of forming large bodies, starting from a sea of equal-sized planetesimals. This is likely one of the earlier steps of planet formation and relevant for the formation of the asteroid belt, the Kuiper belt and…
As many as 5 ice giants--Neptune-mass planets composed of 90% ice and rock and 10% hydrogen--are thought to form at heliocentric distances of 10-25 AU on closely packed orbits spaced ~5 Hill radii apart. Such oligarchies are ultimately…
For grain growth to proceed effectively and lead to planet formation a number of barriers to growth must be overcome. One such barrier, relevant for compact grains in the inner regions of the disc, is the `bouncing barrier' in which large…
We have initiated a large project on identifying the requirements for developing a realistic and ground-up approach to simulating the formation of terrestrial planets in our solar system. As the first phase of this project, we present here…
We investigate planetesimal accretion via a direct N-body simulation of an annulus at 1 AU orbiting a 1 $M_{\odot}$ star. The planetesimal ring, which initially contains N = $10^6$ bodies is evolved into the oligarchic growth phase. Unlike…
Gas giants are thought to form by runaway accretion: an instability driven by the self-gravity of growing atmospheres that causes accretion rates to rise super-linearly with planet mass. Why runaway should stop at a Jupiter or any other…
Anticipating the kinematic constraints from the Gaia mission, we perform an extensive numerical study of the evolution of massive binary systems to predict the peculiar velocities that stars obtain when their companion collapses and…