The stellar IMF from Isothermal MHD Turbulence

Abstract

We address the turbulent fragmentation scenario for the origin of the stellar initial mass function (IMF), using a large set of numerical simulations of randomly driven supersonic MHD turbulence. The turbulent fragmentation model successfully predicts the main features of the observed stellar IMF assuming an isothermal equation of state without any stellar feedback. As a test of the model, we focus on the case of a magnetized isothermal gas, neglecting stellar feedback, while pursuing a large dynamic range in both space and timescales covering the full spectrum of stellar masses from brown dwarfs to massive stars. Our simulations represent a generic 4 pc region within a typical Galactic molecular cloud, with a mass of 3000 Msun and an rms velocity 10 times the isothermal sound speed and 5 times the average Alfven velocity, in agreement with observations. We achieve a maximum resolution of 50 au and a maximum duration of star formation of 4.0 Myr, forming up to a thousand sink particles whose mass distribution closely matches the observed stellar IMF. A large set of medium-size simulations is used to test the sink particle algorithm, while larger simulations are used to test the numerical convergence of the IMF and the dependence of the IMF turnover on physical parameters predicted by the turbulent fragmentation model. We find a clear trend toward numerical convergence and strong support for the model predictions, including the initial time evolution of the IMF. We conclude that the physics of isothermal MHD turbulence is sufficient to explain the origin of the IMF.

25 pages, 21 figures, Accepted by ApJ

References in corpus (14)

• The Boston University-Five College Radio Astronomy Observatory Galactic Ring Survey
• Analytical theory for the initial mass function: CO clumps and prestellar cores
• Modeling Collapse and Accretion in Turbulent Gas Clouds: Implementation and Comparison of Sink Particles in AMR and SPH
• Star formation through gravitational collapse and competitive accretion
• Numerical simulations of compressively driven interstellar turbulence: I. Isothermal gas
• Modeling jet and outflow feedback during star cluster formation
• A simple multigrid scheme for solving the Poisson equation with arbitrary domain boundaries
• Towards a more realistic sink particle algorithm for the RAMSES code
• Infall-Driven Protostellar Accretion and the Solution to the Luminosity Problem
• The statistical properties of stars and their dependence on metallicity: the effects of opacity
• Episodic accretion: the interplay of infall and disc instabilities
• Testing the universality of the IMF with Bayesian statistics: young clusters
• Bondi-Hoyle-Littleton accretion and the upper mass stellar IMF
• Explaining the luminosity spread in young clusters: proto and pre-main sequence stellar evolution in a molecular cloud environment

Cited by in corpus (59)

• The Effect of Jupiter's Formation on the Distribution of Refractory Elements and Inclusions in Meteorites
• STARFORGE: Toward a comprehensive numerical model of star cluster formation and feedback
• The Origin of Massive Stars: The Inertial-Inflow Model
• The dynamics and outcome of star formation with jets, radiation, winds, and supernovae in concert
• A rich population of free-floating planets in the Upper Scorpius young stellar association
• STARFORGE: The effects of protostellar outflows on the IMF
• Effects of the environment and feedback physics on the initial mass function of stars in the STARFORGE simulations
• The Bridge: a transient phenomenon of forming stellar multiples
• Star Formation Regulation and Self-Pollution by Stellar Wind Feedback
• From the CMF to the IMF: Beyond the Core-Collapse Model
• Star formation from dense shocked regions in supersonic isothermal magneto-turbulence
• Explaining the luminosity spread in young clusters: proto and pre-main sequence stellar evolution in a molecular cloud environment
• INFERNO: Galactic winds in dwarf galaxies with star-by-star simulations including runaway stars
• Great Balls of FIRE I: The formation of star clusters across cosmic time in a Milky Way-mass galaxy
• Isothermal Fragmentation: Is there a low-mass cut-off?
• Can magnetized turbulence set the mass scale of stars?
• Pre-supernova feedback sets the star cluster mass function to a power law and reduces the cluster formation efficiency
• The fragmentation properties of massive protocluster gas clumps: an ALMA study
• The contribution of binary star formation via core-fragmentation on protostellar multiplicity
• The emergence of the galactic stellar mass function from a non-universal IMF in clusters
• The origin of free-floating planets
• How magnetic field and stellar radiative feedback influences the collapse and the stellar mass spectrum of a massive star forming clump
• The Core Mass Function in the Orion Nebula Cluster Region: What Determines the Final Stellar Masses?
• The Effect of Supernovae on the Turbulence and Dispersal of Molecular Clouds
• On the origin of magnetic fields in stars II: The effect of numerical resolution
• Testing the Turbulent Origin of the Stellar Initial Mass Function
• Implementation of stellar heating feedback in simulations of star cluster formation: effects on the initial mass function
• Modeling chemistry during star formation: Water deuteration in dynamic star-forming regions
• On the origin of the peak of the stellar initial mass function: exploring the tidal screening theory
• TRAO Survey of Nearby Filamentary Molecular clouds, the Universal Nursery of Stars (TRAO FUNS) I. Dynamics and Chemistry of L1478 in the California Molecular Cloud
• A 3D physico-chemical model of a pre-stellar core. I. Environmental and structural impact on the distribution of CH${}_3$OH and $c$-C${}_3$H${}_2$
• Constraints on the (re-)orientation of star-disk systems through infall
• Environmental variation of the low-mass IMF
• The galaxy-wide stellar initial mass function in the presence of cluster-to-cluster IMF variations
• Role of magnetic fields in the formation of direct collapse black holes
• The Role of Gravity in Producing Power-Law Mass Functions
• The Formation of Protoplanetary Disks through Pre-Main Sequence Bondi-Hoyle Accretion
• Origin and Evolution of Angular Momentum of Class II Disks
• Will ALMA Reveal the True Core Mass Function of Protoclusters?
• The initial mass function of stars and the star-formation rates of galaxies
• Linear dust polarization during the embedded phase of protostar formation
• The influence of the cloud virial parameter on the initial mass function
• Accelerating self-gravitating hydrodynamics simulations with adaptive force updates
• Random gas motions inside sub-parsec scale supercritical filaments
• Prestellar Cores in Turbulent Clouds: Properties of Critical Cores
• Synthetic ngVLA line observations of a massive star-forming cloud
• Late encounter-events as a source of disks and spiral structures -- Forming second generation disks
• The Corona-Australis star-forming region: New insights on its formation history from detailed stellar and disk analysis
• A Search for Evidences of Small-Scale Imhomogeneities in Dense Cores from Line Profile Analysis
• Environmental Effects of Star-Forming Cores on Mass Accretion Rate
• The effects of large scale magnetic fields around young protostars and their disks
• Compact object populations over cosmic time I. BOSSA: a Binary Object environment-Sensitive Sampling Algorithm
• Protostellar disc structure and dynamics during star formation from cloud-scale initial conditions
• Comparison of modified black-body fits for the estimation of dust optical depths in interstellar clouds
• The SPHERE view of multiple star formation
• Physical Properties and Real Nature of Massive Clumps in the Galaxy
• Preferential accretion of binary stars
• The interdependence between density PDF, CMF and IMF and their relation with Mach number in simulations
• The Dynamical State of Massive Clumps