Turbulence-induced disc formation in strongly magnetized cloud cores

Seifried, D.; Banerjee, Rinti; Pudritz, Ralph E.; Klessen, Ralf S.

doi:10.1093/mnras/stt682

Cited by 129 publications

(178 citation statements)

References 66 publications

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“…Santos-Lima et al (2012 attribute the formation of rotationally supported discs to turbulent reconnection occurring in the vicinity of the disc and an associated loss of magnetic flux, which in turn reduces the magnetic braking efficiency. In contrast, in Seifried et al (2012Seifried et al ( , 2013 we suggest that the build-up of Keplerian discs is due to the turbulent motions and the disordered magnetic field structure in the surroundings of the discs rather than due to magnetic flux loss. The turbulent motions distort the magnetic field and hamper the build-up of a toroidal magnetic field component responsible for angular momentum extraction.…”

Section: Introductioncontrasting

confidence: 57%

“…We make use of the sink particle routine (Federrath et al 2010) to model the formation of protostars. The results of the simulations were first presented in Seifried et al (2012Seifried et al ( , 2013. We here only briefly describe the basic setup of the simulations, for more details we refer the reader to the aforementioned papers.…”

Section: Initial Conditions and Basic Resultsmentioning

confidence: 99%

“…At the end of both runs the protostellar discs show a clear Keplerian rotation structure and only mild infall motions (see Fig. 5 in Seifried et al 2013). In Fig.…”

Section: Long-term Evolution Of Protostellar Discsmentioning

confidence: 99%

“…Since we argue in Seifried et al (2012Seifried et al ( , 2013) that the turbulent motions are responsible for the formation Keplerian discs, it is a crucial task to check what minimum strength the turbulent motion must have in order to allow Keplerian discs to form. For the low-mass run M2-NoRot we have seen that already moderate subsonic turbulent motions are sufficient to enable disc formation.…”

Section: Dependence On Turbulence Strengthmentioning

confidence: 99%

“…Also for the other two runs discussed in this section different random seeds for the initial turbulence field are used. We follow the simulations over about 10 kyr after the formation of the first sink particle, which we suppose is sufficient since for corresponding runs discussed in Seifried et al (2012Seifried et al ( , 2013 Keplerian discs were already present after about 5 kyr.…”

Section: Dependence On Turbulence Strengthmentioning

confidence: 99%

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Accretion and magnetic field morphology around Class 0 stage protostellar discs

Seifried

Banerjee

Pudritz

et al. 2014

Monthly Notices of the Royal Astronomical Society

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We analyse simulations of turbulent, magnetised molecular cloud cores focussing on the formation of Class 0 stage protostellar discs and the physical conditions in their surroundings. We show that for a wide range of initial conditions Keplerian discs are formed in the Class 0 stage already. In particular, we show that even subsonic turbulent motions reduce the magnetic braking efficiency sufficiently in order to allow rotationally supported discs to form. We therefore suggest that already during the Class 0 stage the fraction of Keplerian discs is significantly higher than 50%, consistent with recent observational trends but significantly higher than predictions based on simulations with misaligned magnetic fields, demonstrating the importance of turbulent motions for the formation of Keplerian discs. We show that the accretion of mass and angular momentum in the surroundings of protostellar discs occurs in a highly anisotropic manner, by means of a few narrow accretion channels. The magnetic field structure in the vicinity of the discs is highly disordered, revealing field reversals up to distances of 1000 AU. These findings demonstrate that as soon as even mild turbulent motions are included, the classical disc formation scenario of a coherently rotating environment and a well-ordered magnetic field breaks down. Hence, it is highly questionable to assess the magnetic braking efficiency based on non-turbulent collapse simulation. We strongly suggest that, in addition to the global magnetic field properties, the small-scale accretion flow and detailed magnetic field structure have to be considered in order to assess the likelihood of Keplerian discs to be present.

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Section: Introductioncontrasting

confidence: 57%

Section: Initial Conditions and Basic Resultsmentioning

confidence: 99%

“…At the end of both runs the protostellar discs show a clear Keplerian rotation structure and only mild infall motions (see Fig. 5 in Seifried et al 2013). In Fig.…”

Section: Long-term Evolution Of Protostellar Discsmentioning

confidence: 99%

Section: Dependence On Turbulence Strengthmentioning

confidence: 99%

Section: Dependence On Turbulence Strengthmentioning

confidence: 99%

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Accretion and magnetic field morphology around Class 0 stage protostellar discs

Seifried

Banerjee

Pudritz

et al. 2014

Monthly Notices of the Royal Astronomical Society

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Physical Processes in the Interstellar Medium

Klessen

Glover

2015

Saas-Fee Advanced Course

170

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Interstellar space is filled with a dilute mixture of charged particles, atoms, molecules and dust grains, called the interstellar medium (ISM). Understanding its physical properties and dynamical behavior is of pivotal importance to many areas of astronomy and astrophysics. Galaxy formation and evolution, the formation of stars, cosmic nucleosynthesis, the origin of large complex, prebiotic molecules and the abundance, structure and growth of dust grains which constitute the fundamental building blocks of planets, all these processes are intimately coupled to the physics of the interstellar medium. However, despite its importance, its structure and evolution is still not fully understood. Observations reveal that the interstellar medium is highly turbulent, consists of different chemical phases, and is characterized by complex structure on all resolvable spatial and temporal scales. Our current numerical and theoretical models describe it as a strongly coupled system that is far from equilibrium and where the different components are intricately linked together by complex feedback loops. Describing the interstellar medium is truly a multi-scale and multi-physics problem. In these lecture notes we introduce the microphysics necessary to better understand the interstellar medium. We review the relations between large-scale and small-scale dynamics, we consider turbulence as one of the key drivers of galactic evolution, and we review the physical processes that lead to the formation of dense molecular clouds and that govern stellar birth in their interior.

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