Ejection of gaseous clumps from gravitationally unstable protostellar disks

Abstract

We investigate the dynamics of gaseous clumps formed via gravitational fragmentation in young protostellar disks, focusing on the fragments that are ejected from the disk via many-body gravitational interaction. Numerical hydrodynamics simulations were employed to study the evolution of young protostellar disks formed from the collapse of rotating pre-stellar cores with mass in the 1.1-1.6 M_sun range. Protostellar disks formed in our models undergo gravitational fragmentation driven by continuing mass loading from parental collapsing cores. A few fragments can be ejected from the disk during the early evolution, but the low-mass fragments (< 15~M_Jup) disperse creating spectacular bow-type structures while passing through the disk and collapsing core. The least massive fragment that survived the ejection (21 M_Jup) straddles the planetary-mass limit, while the most massive ejected fragments (145 M_Jup) can break up into several pieces, leading to the ejection of wide separation binary clumps in the brown-dwarf mass range. About half of the ejected fragments are gravitationally bound, the majority is supported by rotation against gravity, and all fragments have the specific angular momentum that is much higher than that expected for brown dwarfs. We found that the internal structure of the ejected fragments is distinct from what would be expected for gravitationally contracting clumps formed via cloud core fragmentation, which can help to differentiate their origin. The ejection of fragments is an important process inherent to massive protostellar disks, which produces freely-floating pre-brown dwarf cores, regulates the disk and stellar masses, and potentially enriches the intracluster medium with processed dust and complex organics.

arXiv comment11 pages, 8 figures, accepted for publication by Astronomy & Astrophysics

References in corpus (41)

• Protoplanetary Disks and Their Evolution
• Nonlinear Outcome of Gravitational Instability in Cooling, Gaseous Disks
• Using FU Orionis Outbursts to Constrain Self-Regulated Protostellar Disk Models
• Dense Cores in Dark Clouds. XIV. N2H+(1-0) maps of dense cloud cores
• Analytical theory for the initial mass function: CO clumps and prestellar cores
• Stellar, brown dwarf and multiple star properties from a radiation hydrodynamical simulation of star cluster formation
• The mass function of dense molecular cores and the origin of the IMF
• Stellar, Brown Dwarf, and Multiple Star Properties from Hydrodynamical Simulations of Star Cluster Formation
• Can giant planets form by direct gravitational instability?
• The properties of brown dwarfs and low-mass hydrogen-burning stars formed by disc fragmentation
• The burst mode of accretion and disk fragmentation in the early embedded stages of star formation
• The "Mysterious" Origin of Brown Dwarfs
• The Two Modes of Gas Giant Planet Formation
• Clumps in the Outer Disk by Disk Instability: Why They are Initially Gas Giants and the Legacy of Disruption
• Challenges in Forming Planets by Gravitational Instability: Disk Irradiation and Clump Migration, Accretion & Tidal Destructio
• Accelerated planetesimal growth in self-gravitating protoplanetary discs
• Variable protostellar accretion with episodic bursts
• Nonlinear Outcome of Gravitational Instability in Disks with Realistic Cooling
• Rapid inward migration of planets formed by gravitational instability
• Formation Process of the Circumstellar Disk: Long-term Simulations in the Main Accretion Phase of Star Formation
• Recurrent Planet Formation and Intermittent Protostellar Outflows Induced by Episodic Mass Accretion
• On the convergence of the critical cooling timescale for the fragmentation of self-gravitating discs
• Formation of giant planets and brown dwarfs on wide orbits
• Non-convergence of the critical cooling timescale for fragmentation of self-gravitating discs
• Grain sedimentation inside giant planet embryos
• A Hybrid Scenario for the Formation of Brown Dwarfs and Very Low Mass Stars
• A numerical simulation of a "super-Earth" core delivery from ~ 100 AU to ~ 8 AU
• Tidally induced brown dwarf and planet formation in circumstellar discs
• An analytic column density profile to fit prestellar cores
• Interferometric Identification of a Pre-Brown Dwarf
• IC348-SMM2E: a Class 0 proto-brown dwarf candidate forming as a scaled-down version of low-mass stars
• The properties of discs around planets and brown dwarfs as evidence for disc fragmentation
• Formation of terrestrial planet cores inside giant planet embryos
• Convergence of simulations of self-gravitating accretion discs II: Sensitivity to the implementation of radiative cooling and artificial viscosity
• Fragmenting protostellar disks: properties and observational signatures
• The Tidal Downsizing hypothesis for planet formation and the composition of Solar System comets
• Formation, orbital and thermal evolution, and survival of planetary-mass clumps in the early phase of circumstellar disk evolution
• Lifetime of the embedded phase of low-mass star formation and the envelope depletion rates
• Destruction of massive fragments in protostellar disks and crystalline silicate production
• Very low-luminosity Class I/Flat outflow sources in sigma Orionis
• SMA observations of the proto brown dwarf candidate SSTB213 J041757

Cited by in corpus (25)

• On the existence of accretion-driven bursts in massive star formation
• Forming spectroscopic massive proto-binaries by disk fragmentation
• ALMA Observations of Polarized 872 $\mu$m Dust Emission from the Protostellar Systems VLA 1623 and L1527
• Near-Infrared High-Resolution Imaging Polarimetry of FU Ori-Type Objects: Towards A Unified Scheme for Low-Mass Protostellar Evolution
• Gravitational fragmentation and formation of giant protoplanets on tens-of-au orbits
• The effect of radiative feedback on disc fragmentation
• Gravitoviscous protoplanetary disks with a dust component. I. The importance of the inner sub-au region
• A Tail Structure Associated with Protoplanetary Disk around SU Aurigae
• Large-scale CO spiral arms and complex kinematics associated with the T Tauri star RU Lup
• A likely flyby of binary protostar Z CMa caught in action
• A 1.3 mm SMA Survey of 29 Variable Young Stellar Objects
• Gravitoviscous protoplanetary disks with a dust component. II. Spatial distribution and growth of dust in a clumpy disk
• 1000 AU Exterior Arcs Connected to the Protoplanetary Disk around HL Tau
• Formation of freely floating sub-stellar objects via close encounters
• The Effect of Protoplanetary Disk Cooling Times on the Formation of Gas Giant Planets by Gravitational Instability
• Improving the thin-disk models of circumstellar disk evolution. The 2+1-dimensional model
• The origin of tail-like structures around protoplanetary disks
• A Dual Power Law Distribution for the Stellar Initial Mass Function
• Orbital Migration of Protoplanets in a Marginally Gravitationally Unstable Disk. II. Migration, Merging, and Ejection
• Linear Stability Analysis of a Magnetic Rotating Disk with Ohmic Dissipation and Ambipolar Diffusion
• Signs of outflow feedback from a nearby young stellar object on the protostellar envelope around HL Tau
• The gas disk: Evolution and chemistry
• Using binary statistics in Taurus-Auriga to distinguish between brown dwarf formation processes
• Magnetohydrodynamic Model of Late Accretion onto a Protoplanetary Disk: Cloudlet Encounter Event
• Jammed Keplerian gas leads to the formation and disappearance of spiral arms in a coupled map lattice for astronomical objects