Formation, orbital and thermal evolution, and survival of planetary-mass clumps in the early phase of circumstellar disk evolution

Abstract

We report the results of our three-dimensional radiation hydrodynamics simulation of collapsing unmagnetized molecular cloud cores. We investigate the formation and evolution of the circumstellar disk and the clumps formed by disk fragmentation. Our simulation shows that disk fragmentation occurs in the early phase of circumstellar disk evolution and many clumps form. The clump can be represented by a polytrope sphere of index $n\sim 3$ and $n\gtrsim 4$ at central temperature $T_c\lesssim 100$ K and $T_c\gtrsim 100$ K, respectively. We demonstrate, numerically and theoretically, that the maximum mass of the clump, beyond which it inevitably collapses, is $\sim 0.03M_{\odot }$. The entropy of the clump increases during its evolution, implying that evolution is chiefly determined by mass accretion from the disk rather than by radiative cooling. Although most of the clumps rapidly migrate inward and finally fall onto the protostar, a few clumps remain in the disk. The central density and temperature of the surviving clump rapidly increase and the clump undergoes a second collapse within 1000 - 2000 years after its formation. In our simulation, three second cores of masses $0.2\msun$, $0.15\msun$, and $0.06\msun$ formed. These are protostars or brown dwarfs rather than protoplanets. For the clumps to survive as planetary-mass objects, the rapid mass accretion should be prevented by some mechanisms.

8 pages, 7 figures, accepted for publication in MNRAS, references were modified

References in corpus (10)

• Direct Imaging of Multiple Planets Orbiting the Star HR 8799
• SPLASH: An interactive visualisation tool for Smoothed Particle Hydrodynamics simulations
• The properties of brown dwarfs and low-mass hydrogen-burning stars formed by disc fragmentation
• Magnetic Braking and Protostellar Disk Formation: The Ideal MHD Limit
• Formation Scenario for Wide and Close Binary Systems
• Turbulence-induced disc formation in strongly magnetised cloud cores
• A Semi-Analytical Description for the Formation and Gravitational Evolution of Protoplanetary Disks
• The Burst Mode of Accretion in Primordial Protostars
• Formation and Early Evolution of Circumstellar Disks in Turbulent Molecular Cloud Cores
• An explicit scheme for ohmic dissipation with smoothed particle magneto-hydrodynamics

Cited by in corpus (30)

• Effects of Ohmic and ambipolar diffusion on the formation and evolution of the first cores, protostars and circumstellar discs
• Bimodality of circumstellar disk evolution induced by Hall current
• Investigations of Protostellar Outflow Launching and Gas Entrainment: Hydrodynamic Simulations and Molecular Emission
• Effects of radiation transfer on the structure of self-gravitating disks, their fragmentation and evolution of the fragments
• Signatures of Gravitational Instability in Resolved Images of Protostellar Disks
• The impact of the Hall effect during cloud core collapse:implications for circumstellar disk evolution
• A revised condition for self-gravitational fragmentation of protoplanetary disks
• Protostellar Jets Enclosed by Low-velocity Outflows
• Near-Infrared High-Resolution Imaging Polarimetry of FU Ori-Type Objects: Towards A Unified Scheme for Low-Mass Protostellar Evolution
• Apparent disk-mass reduction and planetesimal formation in gravitationally unstable disks in Class 0/I YSOs
• The migration of gas giant planets in gravitationally unstable discs
• The Origin of the Stellar Mass Distribution and Multiplicity
• Accretion Phase of Star Formation in Clouds with Different Metallicities
• The effect of radiative feedback on disc fragmentation
• Does misalignment between magnetic field and angular momentum enhance or suppress circumstellar disk formation?
• Ejection of gaseous clumps from gravitationally unstable protostellar disks
• Early evolution of disk, outflow, and magnetic field of young stellar objects: Impact of dust model
• Forming Pop III binaries in self-gravitating disks: how to keep the orbital angular momentum
• Evaporation of grain-surface species by shock waves in proto-planetary disk
• Star-disk alignment in the protoplanetary disks: SPH simulation of the collapse of turbulent molecular cloud cores
• The circumstellar disk response to the motion of the host star
• Formation of freely floating sub-stellar objects via close encounters
• Magnetic field and early evolution of circumstellar disks
• One-armed spirals in locally isothermal, radially structured self-gravitating discs
• The dynamical evolution of low-mass hydrogen-burning stars, brown dwarfs and planetary-mass objects formed through disc fragmentation
• Pebble accretion in class 0/I YSOs as a possible pathway for early planet formation
• Improving the thin-disk models of circumstellar disk evolution. The 2+1-dimensional model
• The long-term dynamical evolution of disc-fragmented multiple systems in the Solar Neighborhood
• Gravitational Fragmentation of Extremely Metal-poor Circumstellar Discs
• Fundamental stellar parameters for selected T-Tauri stars in the Chamaeleon and Rho Ophiuchus star-forming regions