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Related papers: Disk Formation in Magnetized Dense Cores with Turb…

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Molecular clouds are observed to be turbulent, but the origin of this turbulence is not well understood. As a result, there are two different approaches to simulating molecular clouds, one in which the turbulence is allowed to decay after…

Astrophysics · Physics 2009-11-13 Stella S. R. Offner , Richard I. Klein , Christopher F. McKee

Pebble accretion is a promising process for decreasing growth timescales of planetary cores, allowing gas giants to form at wide orbital separations. However, nebular turbulence can reduce the efficiency of this gas-assisted growth. We…

Earth and Planetary Astrophysics · Physics 2018-07-18 M. M. Rosenthal , R. A. Murray-Clay , H. B. Perets , N. Wolansky

The temperature of the gas in molecular clouds is a key determinant of the characteristic mass of star formation. Ambipolar diffusion (AD) is considered one of the most important heating mechanisms in weakly ionized molecular clouds. In…

Solar and Stellar Astrophysics · Physics 2015-06-11 Pak Shing Li , Andrew Myers , Christopher F. McKee

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

We present self-similar solutions that describe the gravitational collapse of rotating, isothermal, magnetic molecular-cloud cores, relevant to the formation of rotationally supported protostellar disks. This work focuses on the evolution…

Astrophysics · Physics 2009-11-07 Ruben Krasnopolsky , Arieh Konigl

We consider the accretion process in a disk with magnetic fields that are dragged in from the interstellar medium by gravitational collapse. Two diffusive processes are at work in the system: (1) "viscous" torques exerted by turbulent and…

The stresses produced by magnetorotational turbulence can provide effective angular momentum transport in accretion disks. However, questions remain about the ability of simulated disks to reproduce observationally inferred…

High Energy Astrophysical Phenomena · Physics 2015-06-19 E. R. Parkin

We perform a long-term simulation of star and disk formation using three-dimensional non-ideal magnetohydrodynamics. The simulation starts from a prestellar cloud and proceeds through the long-term evolution of the circumstellar disk until…

Solar and Stellar Astrophysics · Physics 2024-05-15 Masahiro N. Machida , Shantanu Basu

Aspects of turbulence in protostellar accretion discs are being reviewed. The emergence of dead zones due to poor ionization and alternatives to the magneto-rotational instability are discussed. The coupling between dust and gas in…

Astrophysics · Physics 2008-08-08 Axel Brandenburg

Improving our understanding of the initial conditions and earliest stages of star formation is crucial to gain insight into the origin of stellar masses, multiple systems, and protoplanetary disks. We review the properties of low-mass dense…

Astrophysics · Physics 2008-01-29 Philippe André , Shantanu Basu , Shu-ichiro Inutsuka

We perform local, vertically stratified shearing-box MHD simulations of protoplanetary disks (PPDs) at a fiducial radius of 1 AU that take into account the effects of both Ohmic resistivity and ambipolar diffusion (AD). The magnetic…

Earth and Planetary Astrophysics · Physics 2015-06-12 Xue-Ning Bai , James M. Stone

We present high-resolution zoom-in simulations of molecular clouds exposed to an interstellar radiation field and cosmic ray ionisation rate up to 1000 times stronger than that of the solar neighbourhood. We detail the evolution of the…

We present a 3-D ideal MHD simulation of magnetospheric accretion onto a non-rotating star. The accretion process unfolds with intricate 3-D structures driven by various mechanisms. First, the disc develops filaments at the magnetospheric…

Solar and Stellar Astrophysics · Physics 2023-12-18 Zhaohuan Zhu , James M. Stone , Nuria Calvet

We study the effect of stellar evolution on the dispersal of protoplanatary disks by performing one-dimensional simulations of long-term disk evolution. Our simulations include viscous disk accretion, magnetohydrodynamic winds, and…

Earth and Planetary Astrophysics · Physics 2025-03-18 Ayano Komaki , Naoki Yoshida

The origin of disks surrounding young stars has direct implications for our understanding of the formation of planetary systems. In the interstellar clouds from which star form, angular momentum is regulated by magnetic fields, preventing…

Astrophysics · Physics 2007-05-23 Michiel R. Hogerheijde

We review theoretical models of the early stages of star formation, in which gravitational collapse is strongly regulated by magnetic fields and the associated process of ambipolar diffusion. We discuss results of numerical simulations and…

Astrophysics · Physics 2007-05-23 Glenn E. Ciolek , Shantanu Basu

Improving our understanding of the earliest stages of star formation is crucial to gain insight into the origin of stellar masses, multiple systems, and protoplanetary disks. We discuss recent advances made in this area thanks to detailed…

Astrophysics · Physics 2007-05-23 Philippe Andre , Arnaud Belloche , Patrick Hennebelle , Derek Ward-Thompson

Super-sonic turbulence fragments molecular clouds (MC) into a very complex density field with density contrasts of several orders of magnitude. A fraction of the gas is locked into dense and gravitationally bound cores, which collapse as…

Astrophysics · Physics 2007-05-23 Paolo Padoan , AAke Nordlund , Ornolfur Einar Rognvaldsson , Alyssa Goodman

Protoplanetary discs are poorly ionised due to their low temperatures and high column densities, and are therefore subject to three "non-ideal" magnetohydrodynamic effects: Ohmic dissipation, ambipolar diffusion, and the Hall effect. The…

Solar and Stellar Astrophysics · Physics 2014-07-02 Geoffroy Lesur , Matthew W. Kunz , Sebastien Fromang

[Abridged] Star and planet formation are the complex outcomes of gravitational collapse and angular momentum transport mediated by protostellar and protoplanetary disks. In this review we focus on the role of gravitational instability in…

Solar and Stellar Astrophysics · Physics 2016-10-05 Kaitlin M. Kratter , Giuseppe Lodato