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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

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

Properties of candidate stars, forming out of molecular clouds, depend on the ambient conditions of the parent cloud. We present a series of 2D and 3D simulations of fragmentation of molecular clouds in starburst regions as well as clouds…

Solar and Stellar Astrophysics · Physics 2014-11-20 S. Hocuk , M. Spaans

Recent observations of protostellar cores suggest that most of the material in the protostellar phase is accreted along streamers. Streamers in this context are defined as velocity coherent funnels of denser material potentially connecting…

Astrophysics of Galaxies · Physics 2024-06-19 Stefan Heigl , Elena Hoemann , Andreas Burkert

We investigate prestellar core formation and accretion based on three-dimensional hydrodynamic simulations. Our simulations represent local $\sim 1$pc regions within giant molecular clouds where a supersonic turbulent flow converges,…

Solar and Stellar Astrophysics · Physics 2015-06-10 Munan Gong , Eve C. Ostriker

We investigate numerically and semi-analytically the collapse of low-mass, rotating prestellar cores. Initially, the cores are in approximate equilibrium with low rotation (the initial ratio of thermal to gravitational energy is $\alpha_0…

Astrophysics · Physics 2009-11-10 P. Hennebelle , A. Whitworth , S. Cha , S. Goodwin

We revisit our original papers on the burst mode of accretion by incorporating a detailed energy balance equation into a thin-disk model for the formation and evolution of circumstellar disks around low-mass protostars.Our model includes…

Solar and Stellar Astrophysics · Physics 2015-05-19 Eduard I. Vorobyov , Shantanu Basu

We summarize the current status of the turbulent model of star formation in turbulent molecular clouds. In this model, clouds, clumps and cores form a hierarchy of nested density fluctuations caused by the turbulence, and either collapse or…

Astrophysics · Physics 2007-05-23 Enrique Vazquez-Semadeni

We investigate the effect of the turbulent power spectrum (P(k) \propto k^{-n}, with n=3, 4 or 5) on the fragmentation of low-mass cores, by means of SPH simulations. We adopt initial density profiles and low levels of turbulence based on…

Astrophysics · Physics 2009-11-11 S. P. Goodwin , A. P. Whitworth , D. Ward-Thompson

We simulate the early stages of the evolution of turbulent, virialized, high-mass protostellar cores, with primary attention to how cores fragment, and whether they form a small or large number of protostars. Our simulations use the Orion…

Astrophysics · Physics 2008-11-26 Mark R. Krumholz , Richard I. Klein , Christopher F. McKee

We present the results of an ensemble of SPH simulations that follow the evolution of prestellar cores for $0.2\,{\rm Myr}$. All the cores have the same mass, and start with the same radius, density profile, thermal and turbulent energy.…

Solar and Stellar Astrophysics · Physics 2015-06-23 O. Lomax , A. P. Whitworth , D. A. Hubber

Magnetic fields are usually considered dynamically important in star formation when the dimensionless mass-to-flux ratio is close to, or less than, unity (lambda<~1). We show that, in disk formation, the requirement is far less stringent.…

Astrophysics · Physics 2009-11-13 Richard R. Mellon , Zhi-Yun Li

Disc fragmentation provides an important mechanism for producing low mass stars in prestellar cores. Here, we describe Smoothed Particle Hydrodynamics simulations which show how populations of prestellar cores evolve into stars. We find the…

Solar and Stellar Astrophysics · Physics 2016-02-03 O. Lomax , A. P. Whitworth , D. A. Hubber

In this paper, we present the results of 3-dimensional collapse simulations of rotating stars for a range of stellar progenitors. We find that for the fastest spinning stars, rotation does indeed modify the convection above the…

Astrophysics · Physics 2009-11-10 C. L. Fryer , M. S. Warren

Recent studies show that non-radial structures arising from massive star shell convection play an important role in shaping core-collapse supernova explosions. During the collapse phase, convective vortices generate acoustic waves that…

Solar and Stellar Astrophysics · Physics 2024-09-27 Yerassyl Telman , Ernazar Abdikamalov , Thierry Foglizzo

We present the latest development of the disk gravitational instability and fragmentation model, originally introduced by us to explain episodic accretion bursts in the early stages of star formation. Using our numerical hydrodynamics model…

Solar and Stellar Astrophysics · Physics 2015-06-03 Eduard I. Vorobyov , Shantanu Basu

Super-sonic turbulence fragments molecular clouds (MC) into a very complex density field with density contrasts of several orders of magnitude. A fraction of the gas is locked into dense and gravitationally bound cores, which collapse as…

Astrophysics · Physics 2007-05-23 Paolo Padoan , AAke Nordlund , Ornolfur Einar Rognvaldsson , Alyssa Goodman

Fragmentation of filaments into dense cores is thought to be an important step in forming stars. The bar-mode instability of spherically collapsing cores found in previous linear analysis invokes a possibility of re-fragmentation of the…

Solar and Stellar Astrophysics · Physics 2017-06-28 Kazuyuki Sugimura , Yurina Mizuno , Tomoaki Matsumoto , Kazuyuki Omukai

The fragmentation process of primordial-gas cores during prestellar collapse is studied using three-dimensional nested-grid hydrodynamics. Starting from the initial central number density of n \sim10^3 cm^-3, we follow the evolution of…

The fragmentation of molecular cloud cores a factor of 1.1 denser than the critical Bonnor-Ebert sphere is examined though three-dimensional numerical simulations. A nested grid is employed to resolve fine structure down to 1 AU while…

Astrophysics · Physics 2009-11-07 Tomoaki Matsumoto , Tomoyuki Hanawa