Modeling jet and outflow feedback during star cluster formation

Abstract

Powerful jets and outflows are launched from the protostellar disks around newborn stars. These outflows carry enough mass and momentum to transform the structure of their parent molecular cloud and to potentially control star formation itself. Despite their importance, we have not been able to fully quantify the impact of jets and outflows during the formation of a star cluster. The main problem lies in limited computing power. We would have to resolve the magnetic jet-launching mechanism close to the protostar and at the same time follow the evolution of a parsec-size cloud for a million years. Current computer power and codes fall orders of magnitude short of achieving this. In order to overcome this problem, we implement a subgrid-scale (SGS) model for launching jets and outflows, which demonstrably converges and reproduces the mass, linear and angular momentum transfer, and the speed of real jets, with ~ 1000 times lower resolution than would be required without SGS model. We apply the new SGS model to turbulent, magnetized star cluster formation and show that jets and outflows (1) eject about 1/4 of their parent molecular clump in high-speed jets, quickly reaching distances of more than a parsec, (2) reduce the star formation rate by about a factor of two, and (3) lead to the formation of ~ 1.5 times as many stars compared to the no-outflow case. Most importantly, we find that jets and outflows reduce the average star mass by a factor of ~ 3 and may thus be essential for understanding the characteristic mass of the stellar initial mass function.

25 pages, 12 figures, accepted for publication in ApJ, simulation movies available: http://www.ita.uni-heidelberg.de/~chfeder/pubs/outflow_model/outflow_model.shtml?lang=en

References in corpus (33)

• Theory of Star Formation
• The Statistics of Supersonic Isothermal Turbulence
• The Density Probability Distribution in Compressible Isothermal Turbulence: Solenoidal versus Compressive Forcing
• Modeling Collapse and Accretion in Turbulent Gas Clouds: Implementation and Comparison of Sink Particles in AMR and SPH
• Radiation-Hydrodynamic Simulations of Collapse and Fragmentation in Massive Protostellar Cores
• On the Star Formation Efficiency of Turbulent Magnetized Clouds
• The Mass Distribution and Lifetime of Prestellar Cores in Perseus, Serpens, and Ophiuchus
• The Effects of Radiative Transfer on Low-Mass Star Formation
• Simulating the formation of molecular clouds. I. Slow formation by gravitational collapse from static initial conditions
• Magnetic processes in a collapsing dense core. I Accretion and Ejection
• A new Jeans resolution criterion for (M)HD simulations of self-gravitating gas: Application to magnetic field amplification by gravity-driven turbulence
• The Importance of Radiative Feedback for the Stellar Initial Mass Function
• Simulating the formation of molecular clouds. II. Rapid formation from turbulent initial conditions
• The impact of magnetic fields on single and binary star formation
• Numerical simulations of compressively driven interstellar turbulence: I. Isothermal gas
• A SCUBA survey of Orion, the low-mass end of the core mass function
• The evolution of magnetic tower jets in the laboratory
• The Fragmentation of Magnetized, Massive Star-Forming Cores with Radiative Feedback
• Magnetic processes in a collapsing dense core. II Fragmentation. Is there a fragmentation crisis ?
• A robust numerical scheme for highly compressible magnetohydrodynamics: Nonlinear stability, implementation and tests
• The effect of magnetic fields on star cluster formation
• A Direct Multigrid Poisson Solver for Oct-Tree Adaptive Meshes
• Is the Scaling of Supersonic Turbulence Universal?
• PdBI sub-arcsecond study of the SiO microjet in HH212 - Origin and collimation of Class 0 jets
• HH 212: SMA Observations of a Remarkable Protostellar Jet
• The effect of stellar winds on the formation of a protocluster
• Magneto-Hydrodynamics of Population III Star Formation
• Can Protostellar Jets Drive Supersonic Turbulence in Molecular Clouds?
• The structure of molecular clouds and the universality of the clump mass function
• Protostar Mass Due to Infall and Dispersal
• Entrainment Mechanisms for Outflows in the L1551 Star-Forming Region
• Protostellar Outflow Evolution in Turbulent Environments
• Density distributions of outflow driven turbulence

Cited by in corpus (12)

• Inefficient star formation through turbulence, magnetic fields and feedback
• The density structure and star formation rate of non-isothermal polytropic turbulence
• The Turbulent Dynamo in Highly Compressible Supersonic Plasmas
• Protostellar Outflows and Radiative Feedback from Massive Stars
• Time Varying Dynamical Star Formation Rate
• Herschel Observations of the W3 GMC: Clues to the Formation of Clusters of High-Mass Stars
• Formation of young massive clusters from turbulent molecular clouds
• Are turbulent spheres suitable initial conditions for star-forming clouds?
• On the effects of solenoidal and compressive turbulence in prestellar cores
• Stability of filaments in star-forming clouds and the formation of prestellar cores in them
• Power spectra of outflow-driven turbulence
• Formation of prestellar cores via non-isothermal gas fragmentation