Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: The long-term evolution of warped, magnetised discs, and precessing
  outflows in collapsing pre-stellar cores   (abridged) The nature of early Class 0/I protostellar discs is not clearly
understood. Early protostellar discs are needed to drive molecular outflows and
jets observed in star forming regions, but there has been some debate to how
they form. From a theoretical perspective, the consequences of disc and outflow
generation are crucial to understanding the very nature of how stars are
assembled. We have performed 3D ideal magnetohydrodynamic (MHD) simulations of
collapsing Bonnor-Ebert spheres, employing sink particles with a radius of 3.2
AU alongside an AMR grid and using a cooling function to model radiative
cooling of the gas. This has allowed us to explore 2-8x10^4 yr further into the
evolution of an early Class 0 disc-outflow system than previous simulations.
Our outflow is precessing, kinked, turbulent, contains internal shocks and has
a scale of 0.1 pc end-to-end. We form a rotationally dominated disc with a
radius of 100 AU embedded inside a transient, unstable, flattened, rotating
core extending out to 2000 AU. The larger flattened structure launches a low
speed wind (v_r < 1.5 km/s) dominated by B_phi, while the inner disc launches a
centrifugally driven jet dominated by B_p with speeds up to 20$ km/s. From the
inner disk, the value of dM/dt_out/dM/dt_in ~ 0.1, wheras in the outer core
dM/dt_out/dM/dt_in ~ 1.0. The inner disc becomes unstable to a warping
instability due to the magnetic structure of the outflow and warps to 30 deg
with respect to the z-axis by the end of the simulation. The envelope is
cleared out and is less massive than the disc. We measure star formation
efficiencies of eta_core=0.63 (and growing), higher than theoretical
predictions. This indicates that outflows are not as efficient at expelling
envelope mass as some current models estimate. We discuss the relevance of our
disc misalignment concerning the formation of mis-aligned hot Jupiters.

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The categories of this paper are: math
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The categories of this paper are: q-fin
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The categories of this paper are: econ
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The categories of this paper are: hep-lat
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The categories of this paper are: funct-an
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The categories of this paper are: ao-sci
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The categories of this paper are: chao-dyn
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The categories of this paper are: math-ph
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The categories of this paper are: adap-org
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The categories of this paper are: nlin
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The categories of this paper are: dg-ga
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The categories of this paper are: chem-ph
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The categories of this paper are: q-bio
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The categories of this paper are: acc-phys
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The categories of this paper are: patt-sol
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The categories of this paper are: eess