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To study the interaction of star-formation and turbulent molecular cloud structuring, we analyse numerical models and observations of self-gravitating clouds using the Delta-variance as statistical measure for structural characteristics. In…

Astrophysics · Physics 2009-11-07 Volker Ossenkopf , Ralf Klessen , Fabian Heitsch

A fundamental issue in star formation is understanding the precise mechanisms leading to the formation of prestellar cores, and their subsequent gravitationally unstable evolution. To address this question, we carefully construct a suite of…

Astrophysics of Galaxies · Physics 2025-05-13 Sanghyuk Moon , Eve C. Ostriker

Abridged. A large fraction of stars are found in binary systems. It is therefore important for our understanding of the star formation process, to investigate the fragmentation of dense molecular cores. We study the influence of the…

Astrophysics · Physics 2009-11-13 P. Hennebelle , R. Teyssier

Star formation is intimately linked to the dynamical evolution of molecular clouds. Turbulent fragmentation determines where and when protostellar cores form, and how they contract and grow in mass via accretion from the surrounding cloud…

Astrophysics · Physics 2007-05-23 Ralf Klessen

We argue that impact velocities between dust grains with sizes less than $\sim 0.1$ $\mu m$ in molecular cloud cores are dominated by drift arising from ambipolar diffusion. This effect is due to the size dependence of the dust coupling to…

Astrophysics of Galaxies · Physics 2020-09-30 Kedron Silsbee , Alexei Ivlev , Paola Caselli , Olli Sipila , Bo Zhao

Aims: We investigate the behaviour of dust in protoplanetary disks under the action of gas drag in the presence of a planet. Our goal is twofold: to determine the spatial distribution of dust depending on grain size and planet mass, and…

Astrophysics · Physics 2009-11-13 L. Fouchet , S. T. Maddison , J. -F. Gonzalez , J. R. Murray

We study the gravitational fragmentation of circumstellar discs accreting extremely metal-poor ($Z \leq 10^{-3}$ Zsun) gas, performing a suite of three-dimensional hydrodynamic simulations using the adaptive mesh refinement code Enzo. We…

Astrophysics of Galaxies · Physics 2021-10-27 K. Shima , T. Hosokawa

We report results from numerical simulations of star formation in the early universe that focus on gas at very high densities and very low metallicities. We argue that the gas in the central regions of protogalactic halos will fragment as…

Astrophysics · Physics 2009-06-23 Paul C. Clark , Simon C. O. Glover , Ralf S. Klessen

The radial drift and diffusion of dust particles in protoplanetary disks affect both the opacity and temperature of such disks as well as the location and timing of planetesimal formation. In this paper, we present results of numerical…

Earth and Planetary Astrophysics · Physics 2018-10-17 Noemi Schaffer , Chao-Chin Yang , Anders Johansen

Understanding the evolution of dust and molecular hydrogen (H$_2$) is a critical aspect of galaxy evolution, as they affect star formation and the spectral energy distribution of galaxies. We use the $N$-body/smoothed-particle-hydrodynamics…

Astrophysics of Galaxies · Physics 2022-05-25 Leonard E. C. Romano , Kentaro Nagamine , Hiroyuki Hirashita

We present a series of simulations of turbulent stratified protostellar discs with the goal of characterizing the settling of dust throughout a minimum-mass solar nebula. We compare the evolution of both compact spherical grains, as well as…

Astrophysics of Galaxies · Physics 2015-05-14 D. A. Tilley , D. S. Balsara , S. D. Brittain , T. Rettig

Planet formation may begin much earlier than previously expected, when the protoplanetary disk is still massive and gravitationally unstable. It has been proposed that solid grains can concentrate in the spiral arms of self-gravitating…

Earth and Planetary Astrophysics · Physics 2025-11-04 Hans Baehr , Ken Rice , Chao-Chin Yang , Cassandra Hall

We investigate through hydrodynamic simulations the destruction of newly-formed dust grains by sputtering in the reverse shocks of supernova remnants. Using an idealized setup of a planar shock impacting a dense, spherical clump, we implant…

Astrophysics of Galaxies · Physics 2015-05-18 D. W. Silvia , B. D. Smith , J. M. Shull

We present a series of simulations of the fragmentation of a molecular cloud, leading to the formation of a cluster of protostellar cores. The purpose of these simulations is to address a specific numerical problem called artificial…

Astrophysics · Physics 2009-11-11 Hugo Martel , Neal J. Evans , Paul R. Shapiro

The aim of this paper is to study the vertical profile of small dust particles in protoplanetary discs in which angular momentum transport is due to MHD turbulence driven by the magnetorotational instability. We consider particle sizes that…

Earth and Planetary Astrophysics · Physics 2009-11-13 Sebastien Fromang , Richard P. Nelson

We present 3D smoothed particle hydrodynamics simulations of the collapse of clumps formed through gravitational instability in the outer part of a protoplanetary disc. The initial conditions are taken directly from a global disc…

Earth and Planetary Astrophysics · Physics 2015-06-11 M. Galvagni , T. Hayfield , A. C. Boley , L. Mayer , R. Roskar , P. Saha

Dynamic characterization of mechanical properties of dust aggregates has been one of the most important problems to quantitatively discuss the dust growth in protoplanetary disks. We experimentally investigate the dynamic properties of dust…

Earth and Planetary Astrophysics · Physics 2017-12-12 H. Katsuragi , J. Blum

We investigate the formation and early evolution and fragmentation of an accretion disk around a forming massive protostar. We use a grid-based self-gravity-radiation-hydrodynamics code including a sub-grid module for stellar and dust…

Solar and Stellar Astrophysics · Physics 2021-01-04 G. André Oliva , Rolf Kuiper

Mutual sticking of dust aggregates is the first step toward planetesimal formation in protoplanetary disks. In spite that the electric charging of dust particles is well recognized in some contexts, it has been largely ignored in the…

Earth and Planetary Astrophysics · Physics 2011-02-11 Satoshi Okuzumi

Turbulent fragmentation determines where and when protostellar cores form, and how they contract and grow in mass from the surrounding cloud material. This process is investigated, using numerical models of self-gravitating molecular cloud…

Astrophysics · Physics 2010-04-06 Ralf Klessen