Impact of Protostellar Outflows on Turbulence and Star Formation Efficiency in Magnetized Dense Cores

The star-forming efficiency of dense gas is thought to be set within cores by outflow and radiative feedback. We use magnetohydrodynamic simulations to investigate the relation between protostellar outflow evolution, turbulence, and star formation efficiency. We model the collapse and evolution of i...

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Bibliographic Details
Published in:The Astrophysical journal 2017-10, Vol.847 (2), p.104
Main Authors: Offner, Stella S. R., Chaban, Jonah
Format: Article
Language:English
Subjects:
Astrophysics
ASTROPHYSICS, COSMOLOGY AND ASTRONOMY
Computational fluid dynamics
Computer simulation
COMPUTERIZED SIMULATION
Cores
Deposition
Efficiency
Evolution
Feedback
Field strength
Fluid flow
ISM: jets and outflows
MAGNETIC FIELDS
Magnetohydrodynamic simulation
Magnetohydrodynamic turbulence
MAGNETOHYDRODYNAMICS
MASS
Momentum
Outflow
PROTOSTARS
Radiation
Star & galaxy formation
STAR EVOLUTION
Star formation
STARS
Stars & galaxies
stars: formation
stars: low-mass
stars: winds, outflows
Stellar evolution
STELLAR WINDS
TURBULENCE
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Summary:The star-forming efficiency of dense gas is thought to be set within cores by outflow and radiative feedback. We use magnetohydrodynamic simulations to investigate the relation between protostellar outflow evolution, turbulence, and star formation efficiency. We model the collapse and evolution of isolated dense cores for 0.5 Myr including the effects of turbulence, radiation transfer, and both radiation and outflow feedback from forming protostars. We show that outflows drive and maintain turbulence in the core environment even with strong initial fields. The star formation efficiency decreases with increasing field strength, and the final efficiencies are 15%-40%. The Stage 0 lifetime, during which the protostellar mass is lower than that of the dense envelope, increases proportionally with the initial magnetic field strength and ranges from . The average accretion rate is well represented by a tapered turbulent core model, which is a function of the final protostellar mass and is independent of the magnetic field strength. By tagging material launched in the outflow, we demonstrate that the outflow entrains about three times the actual launched gas mass, a ratio that remains roughly constant in time regardless of the initial magnetic field strength. However, turbulent driving increases for stronger fields since momentum is more efficiently imparted to non-outflow material. The protostellar outflow momentum is highest during the first 0.1 Myr and declines thereafter by a factor of as the accretion rate diminishes.
ISSN:0004-637X
1538-4357
DOI:10.3847/1538-4357/aa8996