Slingshot Mechanism for Clusters: Gas Density Regulates Star Density in the Orion Nebula Cluster (M42)

Abstract

We characterize the stellar and gas volume density, potential, and gravitational field profiles in the central $\sim$ 0.5 pc of the Orion Nebula Cluster (ONC), the nearest embedded star cluster (or rather, proto-cluster) hosting massive star formation available for detailed observational scrutiny. We find that the stellar volume density is well characterized by a Plummer profile ${\rho }_{stars}(r)=5755{\mathrm{M}}_{\odot }{\mathrm{pc}}^{-3}(1+(r/a{)}^2{)}^{-5/2}$, where $a=0.36$ pc. The gas density follows a cylindrical power law ${\rho }_{gas}(R)=25.9{\mathrm{M}}_{\odot }{\mathrm{pc}}^{-3}(R/\mathrm{pc}{)}^{-1.775}$. The stellar density profile dominates over the gas density profile inside $r\sim 1$ pc. The gravitational field is gas-dominated at all radii, but the contribution to the total field by the stars is nearly equal to that of the gas at $r\sim a$. This fact alone demonstrates that the proto-cluster cannot be considered a gas-free system or a virialized system dominated by its own gravity. The stellar proto-cluster core is dynamically young, with an age of $\sim$ 2-3 Myr, a 1D velocity dispersion of ${\sigma }_{\mathrm{obs}}=2.6$ km s${}^{-1}$, and a crossing time of $\sim$ 0.55 Myr. This timescale is almost identical to the gas filament oscillation timescale estimated recently by Stutz & Gould (2016). This provides strong evidence that the proto-cluster structure is regulated by the gas filament. The proto-cluster structure may be set by tidal forces due to the oscillating filamentary gas potential. Such forces could naturally suppress low density stellar structures on scales $\gtrsim a$. The analysis presented here leads to a new suggestion that clusters form by an analog of the "slingshot mechanism" previously proposed for stars.

11 pages, 11 figures, MNRAS accepted

References in corpus (13)

• The distance to the Orion Nebula
• A Spitzer Survey of Young Stellar Clusters within One Kiloparsec of the Sun: Cluster Core Extraction and Basic Structural Analysis
• The Gould's Belt Distances Survey (GOBELINS) II. Distances and structure towards the Orion Molecular Clouds
• A Large Catalog of Accurate Distances to Molecular Clouds from PS1 Photometry
• On the Structure of the Orion A Cloud and the Formation of the Orion Nebula Cluster
• A Parallactic Distance of 389 +24/-21 parsecs to the Orion Nebula Cluster from Very Long Baseline Array Observations
• Evolution of column density distributions within Orion~A
• Gravitational collapse of the OMC-1 region
• Age Gradients in the Stellar Populations of Massive Star Forming Regions Based on a New Stellar Chronometer
• The Structure, Dynamics and Star Formation Rate of the Orion Nebula Cluster
• Characterization of the velocity anisotropy of accreted globular clusters
• Magnetic tension and instabilities in the Orion A integral shaped filament
• Dynamical Ejections of Stars due to an Accelerating Gas Filament

Cited by in corpus (39)

• ATOMS: ALMA Three-millimeter Observations of Massive Star-forming regions -- I. Survey description and a first look at G9.62+0.19
• Final Targeting Strategy for the SDSS-IV APOGEE-2S Survey
• ALMA-IMF I -- Investigating the origin of stellar masses: Introduction to the Large Program and first results
• Distribution of Serpens South protostars revealed with ALMA
• Dynamical evolution of stars and gas of young embedded stellar sub-clusters
• Large-scale periodic velocity oscillation in the filamentary cloud G350.54+0.69
• The Formation of Solar System Analogs in Young Star Clusters
• Gaia Stellar Kinematics in the Head of the Orion A Cloud: Runaway Stellar Groups and Gravitational Infall
• The 3-D Kinematics of the Orion Nebula Cluster: NIRSPEC-AO Radial Velocities of the Core Population
• An HST Survey of Protostellar Outflow Cavities: Does Feedback Clear Envelopes?
• Magnetic fields in star forming systems (I): Idealized synthetic signatures of dust polarization and Zeeman splitting in filaments
• Gas velocity structure of the Orion A Integral Shaped Filament
• Surveying the Giant HII Regions of the Milky Way with SOFIA: I. W51A
• Filament rotation in the California L1482 cloud
• Magnetic tension and instabilities in the Orion A integral shaped filament
• Low Mass Stars as Tracers of Star and Cluster Formation
• The straight and isolated G350.54+0.69 filament: density profile and star formation content
• ALMA-IMF XIII: N${}_2$H${}^{+}$ kinematic analysis on the intermediate protocluster G353.41
• Stellar Properties for a Comprehensive Collection of Star Forming Regions in the SDSS APOGEE-2 Survey
• Dynamical Ejections of Stars due to an Accelerating Gas Filament
• The Herschel Orion Protostar Survey: Far-Infrared Photometry and Colors of Protostars and Their Variations across Orion A and B
• The APEX Large CO Heterodyne Orion Legacy Survey (ALCOHOLS). I. Survey overview
• Emergence of high-mass stars in complex fiber networks (EMERGE). I. Early ALMA Survey: observations and massive data reduction
• Magnetic fields in star-forming systems (II): examining dust polarization, the Zeeman effect, and the Faraday rotation measure as magnetic field tracers
• ALMA-IMF XVI: Mass-averaged temperature of cores and protostellar luminosities in the ALMA-IMF protoclusters
• ALMA-IMF XVIII: The assembly of a star cluster: Dense N${}_2$H${}^{+}$ (1-0) kinematics in the massive G351.77 protocluster
• Simulated observations of star formation regions: infrared evolution of globally collapsing clouds
• Understanding the Star Formation Efficiency in Dense Gas: Initial Results from the CAFFEINE Survey with ArTéMiS
• Benchmarking the IRDC G351.77-0.53: Gaia DR3 distance, mass distribution, and star formation content
• The 3D Kinematics of the Orion Nebula Cluster II: Mass-dependent Kinematics of the Inner Cluster
• The CARMA-NRO Orion Survey: Core Emergence and Kinematics in the Orion A Cloud
• Kinematics of Subclusters in Star Cluster Complexes: Imprint of their Parental Molecular Clouds
• Symmetry properties and widths of the filamentary structures in the Orion A giant molecular cloud
• Completing the Protostellar Luminosity Function in Cygnus-X with SOFIA/FORCAST Imaging
• Massive star cluster formation III. Early mass segregation during cluster assembly
• Stirred, not shaken: Star cluster survival in the slingshot scenario
• Dust trapping in protoplanetary discs after stellar flybys
• The Impact of Expanding HII Regions on Filament G37:Curved Magnetic Field and Multiple Direction Material Flows
• Centrally concentrated star formation in young clusters