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Related papers: Protostellar Disk Dynamos and Hydromagnetic Outflo…

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The driving mechanism of protostellar outflows and jets and their effects on the star formation process obtained from recent theoretical and numerical studies are described. Low-velocity outflows are driven by an outer region of the…

Astrophysics of Galaxies · Physics 2017-11-02 Masahiro N. Machida

(Abridged) In this review we focus on the observations and theory of the formation of early disks and outflows, and their connections with the first phases of planet formation. Large rotationally supported circumstellar disks, although…

Solar and Stellar Astrophysics · Physics 2015-06-18 Zhi-Yun Li , Robi Banerjee , Ralph E. Pudritz , Jes K. Jørgensen , Hsien Shang , Ruben Krasnopolsky , Anaëlle Maury

Like their lower mass siblings, massive protostars can be expected to: a) be surrounded by circumstellar disks and b) launch magnetically-driven jets and outflows. The disk formation and global evolution is thereby controlled by advection…

Solar and Stellar Astrophysics · Physics 2023-01-18 André Oliva , Rolf Kuiper

Magnetic fields are usually considered dynamically important in star formation when the dimensionless mass-to-flux ratio is close to, or less than, unity (lambda<~1). We show that, in disk formation, the requirement is far less stringent.…

Astrophysics · Physics 2009-11-13 Richard R. Mellon , Zhi-Yun Li

The formation and evolution of a circumstellar disk in magnetized cloud cores is investigated from prestellar core stage until sim 10^4 yr after protostar formation. In the circumstellar disk, fragmentation first occurs due to gravitational…

Solar and Stellar Astrophysics · Physics 2015-05-27 Masahiro N. Machida , Shu-ichiro Inutsuka , Tomoaki Matsumoto

The role of magnetic fields for the formation of planets is reviewed. Protoplanetary disc turbulence driven by the magnetorotational instability has a huge influence on the early stages of planet formation. Small dust grains are transported…

Earth and Planetary Astrophysics · Physics 2015-05-13 Anders Johansen

Forming massive stars launch outflows of magnetic origin, which in fact serve as a marker for finding sites of massive star formation. However, both the theoretical and observational study of the mechanisms that intervene in the formation…

Solar and Stellar Astrophysics · Physics 2023-01-18 André Oliva , Rolf Kuiper

Truncated abstract: The formation of a protostellar disc is a natural outcome during the star formation process. As gas in a molecular cloud core collapses under self-gravity, the angular momentum of the gas will slow its collapse on small…

Solar and Stellar Astrophysics · Physics 2018-12-18 James Wurster , Zhi-Yun Li

The formation of protostellar disks out of molecular cloud cores is still not fully understood. Under ideal MHD conditions, the removal of angular momentum from the disk progenitor by the typically embedded magnetic field may prevent the…

Astrophysics of Galaxies · Physics 2015-05-30 R. Santos-Lima , E. M. de Gouveia Dal Pino , A. Lazarian

We present a theoretical model for primordial star formation. First we describe the structure of the initial gas cores as virialized, quasi-hydrostatic objects in accord with recent high resolution numerical studies. The accretion rate can…

Astrophysics · Physics 2009-11-10 Jonathan C. Tan , Christopher F. McKee

While magnetic fields are important in contemporary star formation, their role in primordial star formation is unknown. Magnetic fields of order 10^-16 G are produced by the Biermann battery due to the curved shocks and turbulence…

Astrophysics of Galaxies · Physics 2020-07-15 Christopher F. McKee , Athena Stacy , Pak Shing Li

Although protostars and disks are often studied separately owing to numerical and observational challenges, breakthroughs in recent years have highlighted the need to study both objects in concert. The role of magnetic fields in this regard…

Solar and Stellar Astrophysics · Physics 2025-04-30 Adnan Ali Ahmad , Matthias González , Patrick Hennebelle , Ugo Lebreuilly , Benoît Commerçon

Many types of stars have strong magnetic fields that can dynamically influence the flow of circumstellar matter. In stars with accretion disks, the stellar magnetic field can truncate the inner disk and determine the paths that matter can…

Solar and Stellar Astrophysics · Physics 2016-05-18 M. M. Romanova , S. P. Owocki

The formation of a star is a dynamic process fed by the gravitational collapse of a molecular cloud core. Theoretical models and observations suggest that the majority of this infalling material settles into a protoplanetary disk before…

Astrophysics of Galaxies · Physics 2017-12-08 Doug Johnstone

We consider formation of accretion disks from a realistically turbulent molecular gas using 3D MHD simulations. In particular, we analyze the effect of the fast turbulent reconnection described by the Lazarian & Vishniac (1999) model for…

Solar and Stellar Astrophysics · Physics 2016-03-16 Diego F. González-Casanova , Reinaldo Santos-Lima , Alexander Lazarian

Through the magnetic braking and the launching of protostellar outflows, magnetic fields play a major role in the regulation of angular momentum in star formation, which directly impacts the formation and evolution of protoplanetary disks…

Solar and Stellar Astrophysics · Physics 2020-09-04 Pierre Marchand , Kengo Tomida , Kei Tanaka , Benoît Commerçon , Gilles Chabrier

Magnetic fields play a vital role in numerous astrophysical processes such as star formation and the interstellar medium. In particular, their role in the formation and evolution of galaxies is not well understood. This paper presents…

Astrophysics of Galaxies · Physics 2021-12-10 Huai-Hsuan Chiu , Ke-Jung Chen

The accretion phase of star formation is investigated in magnetically-dominated clouds that have an initial subcritical mass-to-flux ratio. We employ nonideal magnetohydrodynamic simulations that include ambipolar diffusion and ohmic…

Solar and Stellar Astrophysics · Physics 2020-03-18 Masahiro N. Machida , Shantanu Basu

Understanding the physics of how stars form is a highly-prioritized goal of modern Astrophysics, in part because star formation is linked to both galactic dynamics on large scales and to the formation of planets on small scales. It is…

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

Astrophysics of Galaxies · Physics 2017-10-04 Stella S. R. Offner , Jonah Chaban