The extreme initial kinetic energy allowed by a collapsing turbulent core

Abstract

We present high-resolution hydrodynamical simulations aimed at following the gravitational collapse of a gas core, in which a turbulent spectrum of velocity is implemented only initially. We determine the maximal value of the ratio of kinetic energy to gravitational energy, denoted here by ${\left(\frac{E_{\mathrm{kin}}}{E_{\mathrm{grav}}}\right)}_{\max }$, so that the core (i) will collapse around one free-fall time of time evolution or (ii) will expand unboundedly, because it has a value of $\frac{E_{\mathrm{kin}}}{E_{\mathrm{grav}}}$ larger than ${\left(\frac{E_{\mathrm{kin}}}{E_{\mathrm{grav}}}\right)}_{\max }$. We consider core models with a uniform or centrally condensed density profile and with velocity spectra composed of a linear combination of one-half divergence-free turbulence type and the other half of a curl-free turbulence type. We show that the outcome of the core collapse are protostars forming either (i) a multiple system obtained from the fragmentation of filaments and (ii) a single primary system within a long filament. In addition, some properties of these protostars are also determined and compared with those obtained elsewhere.

References in corpus (28)

• The cosmological simulation code GADGET-2
• GADGET: A code for collisionless and gasdynamical cosmological simulations
• The Stellar IMF from Turbulent Fragmentation
• Cold Dark Clouds: The Initial Conditions for Star Formation
• Modelling Accretion in Protobinary Systems
• Comparing the statistics of interstellar turbulence in simulations and observations: Solenoidal versus compressive turbulence forcing
• The Formation of a Star Cluster: Predicting the Properties of Stars and Brown Dwarfs
• The Star Formation Rate of Turbulent Magnetized Clouds: Comparing Theory, Simulations, and Observations
• SPLASH: An interactive visualisation tool for Smoothed Particle Hydrodynamics simulations
• Dense Cores in Dark Clouds. XIV. N2H+(1-0) maps of dense cloud cores
• Modeling Collapse and Accretion in Turbulent Gas Clouds: Implementation and Comparison of Sink Particles in AMR and SPH
• The Formation Mechanism of Brown Dwarfs
• The Formation of Close Binary Systems by Dynamical Interactions and Orbital Decay
• Inefficient star formation through turbulence, magnetic fields and feedback
• Simulating star formation in molecular cloud cores I. The influence of low levels of turbulence on fragmentation and multiplicity
• Smoothed Particle Hydrodynamics with particle splitting, applied to self-gravitating collapse
• Importance of the Initial Conditions for Star Formation - I. Cloud Evolution and Morphology
• An empirical model for protostellar collapse
• A General Theory of Turbulent Fragmentation
• Simulating star formation in molecular cores II. The effects of different levels of turbulence
• Centrally condensed turbulent cores: Massive stars or fragmentation?
• The influence of the turbulent perturbation scale on prestellar core fragmentation and disk formation
• Star formation in molecular cores III. The effect of the turbulent power spectrum
• Simulating star formation in molecular cloud cores IV. The role of turbulence and thermodynamics
• An Observational Method to Measure the Relative Fractions of Solenoidal and Compressible Modes in Interstellar Clouds
• On the effects of solenoidal and compressive turbulence in prestellar cores
• Gravitational Collapse and Fragmentation in Molecular Clouds with Adaptive Mesh Refinement
• Comparing binary systems from rotating parent gas structures with different total masses

Cited by in corpus (2)

• Empirical formulae to describe some physical properties of small groups of protogalaxies with multiplicity
• The effects of a compressive velocity pulse on a collapsing turbulent clump