A stochastic and analytical model of hierarchical fragmentation: The fragmentation of gas structures into young stellar objects in the interstellar medium
arXiv:2408.02472 · doi:10.1051/0004-6361/202449649
Abstract
Molecular clouds are the most important incubators of young stars clustered in various stellar structures whose spatial extension can vary from a few AU to several thousand AU. Although the reality of these stellar systems has been established, the physical origin of their multiplicity remains an open question. Our aim was to characterise these stellar groups at the onset of their formation by quantifying both the number of stars they contain and their mass using a hierarchical fragmentation model of the natal molecular cloud. We developed a stochastic and predictive model that reconciles the continuous multi-scale structure of a fragmenting molecular cloud with the discrete nature of the stars that are the products of this fragmentation. This model was implemented within a gravo-turbulent fragmentation framework to analytically follow the fragmentation properties along spatial scales using an isothermal and adiabatic equations of state (EOSs). Using an adiabatic EOS we determined a characteristic spatial scale where further fragmentation is prevented, around a few tens of AU. We show that fragmentation is a self-regulated process as fragments tend to become marginally unstable following a Bonnor-Ebert-like mass-size profile. Supersonic turbulent fragmentation structures the cloud down to pc, and gradually turns into a less productive Jeans-type fragmentation under subsonic conditions so hierarchical fragmentation is a scale dependant process. Our work suggests that pre-stellar objects resulting from gas fragmentation, have to progressively increase their accretion rate in order to form stars. A hierarchical fragmentation scenario is compatible with both the multiplicity of stellar systems identified in Taurus and the multi-scale structure extracted within NGC 2264 molecular cloud.
References in corpus (41)
- Embedded Clusters in Molecular Clouds
- Stellar Multiplicity
- The Stellar IMF from Turbulent Fragmentation
- Analytical theory for the initial mass function: CO clumps and prestellar cores
- The mass function of dense molecular cores and the origin of the IMF
- Global Hierarchical Collapse In Molecular Clouds. Towards a Comprehensive Scenario
- Density probability distribution in one-dimensional polytropic gas dynamics
- Turbulent molecular clouds
- A Theory of the IMF for Star Formation in Molecular Clouds
- On the Density Distribution in Star-forming Interstellar Clouds
- Accretion in stellar clusters and the IMF
- Modeling UV Radiation Feedback from Massive Stars: II. Dispersal of Star-Forming Giant Molecular Clouds by Photoionization and Radiation Pressure
- Radiation-Hydrodynamic Simulations of the Formation of Orion-Like Star Clusters II. The Initial Mass Function from Winds, Turbulence, and Radiation
- A Holistic Scenario of Turbulent Molecular Cloud Evolution and Control of the Star Formation Efficiency. First Tests
- Gravity or turbulence? -III. Evidence of pure thermal Jeans fragmentation at ~0.1 pc scale
- The Mass Distributions of Starless and Protostellar Cores in Gould Belt Clouds
- An Excursion-Set Model for the Structure of GMCs and the ISM
- A supersonic turbulence origin of Larson's laws
- Testing Larson's relationships in massive clumps
- The W43-MM1 mini-starburst ridge, a test for star formation efficiency models
- The Minimum Mass for Opacity-Limited Fragmentation in Turbulent Cloud Cores
- Stringent limits on the magnetic field strength in the disc of TW Hya: ALMA observations of CN polarisation
- Hierarchical fragmentation in the Perseus molecular cloud: From the cloud scale to protostellar objects
- Stellar mass spectrum within massive collapsing clumps II. Thermodynamics and tidal forces of the first Larson core
- Universal Scaling Relations in Scale-Free Structure Formation
- Massive stars reveal variations of the stellar initial mass function in the Milky Way stellar clusters
- Multiplicity and clustering in Taurus star forming region. II. From ultra-wide pairs to dense NESTs
- Mapping the core mass function to the initial mass function
- Multiplicity and clustering in Taurus star-forming region. I. Unexpected ultra-wide pairs of high-order multiplicity in Taurus
- Energy budget of forming clumps in numerical simulations of collapsing clouds
- Isothermal Fragmentation: Is there a low-mass cut-off?
- Magnetic fields in circumstellar disks: The potential of Zeeman observations
- Observing Turbulent Fragmentation in Simulations: Predictions for CARMA and ALMA
- Strong dependence of the physical properties of cores on spatial resolution in observations and simulations
- Submillimeter Array Observations of NGC 2264-C: Molecular Outflows and Driving Sources
- The Effect of Supernovae on the Turbulence and Dispersal of Molecular Clouds
- On the emergent System Mass Function: the contest between accretion and fragmentation
- S2D2: Small-scale Significant substructure DBSCAN Detection I. NESTs detection in 2D star-forming regions
- Cloud Dispersal in Turbulent Flows
- A graph theory-based multi-scale analysis of hierarchical cascade in molecular clouds : Application to the NGC 2264 region
- Turbulent Fragmentation and Star Formation