Angular Momenta, Magnetization, and Accretion of Protostellar Cores. (arXiv:2003.13697v1 [astro-ph.SR])
<a href="http://arxiv.org/find/astro-ph/1/au:+Kuznetsova_A/0/1/0/all/0/1">Aleksandra Kuznetsova</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Hartmann_L/0/1/0/all/0/1">Lee Hartmann</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Heitsch_F/0/1/0/all/0/1">Fabian Heitsch</a>
Building on our previous hydrodynamic study of the angular momenta of cloud
cores formed during gravitational collapse of star-forming molecular gas in our
previous work, we now examine core properties assuming ideal
magnetohydrodynamics (MHD). Using the same sink-patch implementation for the
emph{Athena} MHD code, we characterize the statistical properties of cores,
including the mass accretion rates, specific angular momenta, and alignments
between the magnetic field and the spin axis of the core on the $0.1
mathrm{pc}$ scale. Our simulations, which reproduce the observed relation
between magnetic field strength and gas density, show that magnetic fields can
help collimate low density flows and help seed the locations of filamentary
structures. Consistent with our previous purely hydrodynamic simulations, stars
(sinks) form within the heterogeneous environments of filaments, such that
accretion onto cores is highly episodic leading to short-term variability but
no long-term monotonic growth of the specific angular momenta. With statistical
characterization of protostellar cores properties and behaviors, we aim to
provide a starting point for building more realistic and self-consistent disk
formation models, helping to address whether magnetic fields can prevent the
development of (large) circumstellar disks in the ideal MHD limit.
Building on our previous hydrodynamic study of the angular momenta of cloud
cores formed during gravitational collapse of star-forming molecular gas in our
previous work, we now examine core properties assuming ideal
magnetohydrodynamics (MHD). Using the same sink-patch implementation for the
emph{Athena} MHD code, we characterize the statistical properties of cores,
including the mass accretion rates, specific angular momenta, and alignments
between the magnetic field and the spin axis of the core on the $0.1
mathrm{pc}$ scale. Our simulations, which reproduce the observed relation
between magnetic field strength and gas density, show that magnetic fields can
help collimate low density flows and help seed the locations of filamentary
structures. Consistent with our previous purely hydrodynamic simulations, stars
(sinks) form within the heterogeneous environments of filaments, such that
accretion onto cores is highly episodic leading to short-term variability but
no long-term monotonic growth of the specific angular momenta. With statistical
characterization of protostellar cores properties and behaviors, we aim to
provide a starting point for building more realistic and self-consistent disk
formation models, helping to address whether magnetic fields can prevent the
development of (large) circumstellar disks in the ideal MHD limit.
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