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We investigate the evolution of non-adiabatic collapse of a shear-free spherically symmetric stellar configuration with anisotropic stresses accompanied with radial heat flux. The collapse begins from a curvature singularity with infinite…

General Relativity and Quantum Cosmology · Physics 2013-04-30 R. Sharma , R. Tikekar

The thermal and chemical evolution of gravitationally collapsing protostellar clouds is investigated, focusing attention on their dependence on metallicity. Calculations are carried out for a range of metallicities spanning the local…

Astrophysics · Physics 2009-10-31 Kazuyuki Omukai

We study the self-similar collapse of an isothermal magnetized rotating cloud in the ideal magnetohydrodynamic (MHD) regime. In the limit of small distance from the accreting protostar we find an analytic solution that corresponds to…

Astrophysics · Physics 2008-11-26 D. Galli , S. Lizano , F. H. Shu , A. Allen

The birth and death of planets may be affected by mass outflows from their parent stars during the T-Tauri or post-main-sequence phases of stellar evolution. These outflows are often modelled to be isotropic, but this assumption is not…

Earth and Planetary Astrophysics · Physics 2015-06-16 Dimitri Veras , John D. Hadjidemetriou , Christopher A. Tout

In this work, the gas infall and the formation of outflows around low and high mass protostars are investigated. A radial self-similar approach to model the transit of the molecular gas around the central object is employed. We include…

Astrophysics · Physics 2009-11-13 C. Combet , T. Lery , G. C. Murphy

We study the formation and evolution of several molecules in a collapsing interstellar cloud using a reasonably large reaction network containing more then four hundred atomic and molecular species. We employ a time dependent, spherically…

Astrophysics · Physics 2009-06-30 Ankan Das , Sandip Kumar Chakrabarti , Kinsuk Acharyya , Sonali Chakrabarti

The protostellar collapse of a molecular cloud core is usually accompanied by outflow phenomena. The latter are thought to be driven by magnetorotational processes from the central parts of the protostellar disc. While several 3D AMR/nested…

Solar and Stellar Astrophysics · Physics 2015-05-30 Florian Bürzle , Paul C. Clark , Federico Stasyszyn , Klaus Dolag , Ralf S. Klessen

We investigate the formation and early evolution of a protostellar disc from a magnetized pre-stellar core using non-ideal magnetohydrodynamic (MHD) simulations including ambipolar diffusion and Ohmic dissipation. The dynamical contraction…

Solar and Stellar Astrophysics · Physics 2021-02-17 Wenrui Xu , Matthew W. Kunz

Dynamical collapses of magnetized molecular cloud cores are studied with magnetohydrodynamical simulations from the run-away collapse phase to the accretion phase. In the run-away collapse phase, a disk threaded by magnetic field lines is…

Astrophysics · Physics 2009-10-30 Kohji Tomisaka

A fundamental issue in star formation is understanding the precise mechanisms leading to the formation of prestellar cores, and their subsequent gravitationally unstable evolution. To address this question, we carefully construct a suite of…

Astrophysics of Galaxies · Physics 2025-05-13 Sanghyuk Moon , Eve C. Ostriker

We investigate numerically and semi-analytically the collapse of low-mass, rotating prestellar cores. Initially, the cores are in approximate equilibrium with low rotation (the initial ratio of thermal to gravitational energy is $\alpha_0…

Astrophysics · Physics 2009-11-10 P. Hennebelle , A. Whitworth , S. Cha , S. Goodwin

Self-gravitating galactic halos composed of self-interacting dark matter exhibit the formation of a highly dense core at the galactic center--a gravothermal collapse. Analytic models to describe this evolution have been developed and…

Cosmology and Nongalactic Astrophysics · Physics 2025-10-29 Marc Kamionkowski , Kris Sigurdson

We report the first three-dimensional radiation magnetohydrodynamic (RMHD) simulations of protostellar collapse with and without Ohmic dissipation.We take into account many physical processes required to study star formation processes,…

Solar and Stellar Astrophysics · Physics 2015-03-20 Kengo Tomida , Kohji Tomisaka , Tomoaki Matsumoto , Yasunori Hori , Satoshi Okuzumi , Masahiro N. Machida , Kazuya Saigo

The coupling between the magnetic field and the gas during the collapsing phase of star-forming cores is strongly affected by the dust size distribution, which is expected to evolve. We aim to investigate the influence of key parameters on…

Solar and Stellar Astrophysics · Physics 2024-10-02 Valentin Vallucci-Goy , Ugo Lebreuilly , Patrick Hennebelle

The birth process of circumstellar disks remains poorly constrained due to observational and numerical challenges. Recent numerical works have shown that the small-scale physics, often wrapped into a sub-grid model, play a crucial role in…

Solar and Stellar Astrophysics · Physics 2024-07-03 Adnan Ali Ahmad , Matthias González , Patrick Hennebelle , Benoît Commerçon

An hourglass-shaped magnetic field pattern arises naturally from the gravitational collapse of a star-forming gas cloud. Most studies have focused on the prestellar collapse phase, when the structure has a smooth and monotonic radial…

Solar and Stellar Astrophysics · Physics 2024-06-10 Shantanu Basu , Xiyuan Li , Gianfranco Bino

We study the formation of the protoplanetary disk by the collapse of a primordial molecular cloud, and how its evolution leads to the selection of specific types of planets. We use a hydrodynamical code that accounts for the dynamics,…

Earth and Planetary Astrophysics · Physics 2019-04-17 Kevin Baillié , Joao Marques , Laurent Piau

We present numerical simulations of the evolution of low-mass, isothermal, molecular cores which are subjected to an increase in external pressure $P\xt$. If $P\xt$ increases very slowly, the core approaches instability quite…

Astrophysics · Physics 2009-11-07 P. Hennebelle , A. P. Whitworth , P. P. Gladwin , Ph. Andre

We study the gravitational collapse of a spherically symmetric anisotropic relativistic star within Einstein theory of gravity making use of one of our recently developed collapsing stellar models [{\it Astrophys. Space Sci.} {\bf361} 99…

General Relativity and Quantum Cosmology · Physics 2022-01-05 Shyam Das , Bikash Chandra Paul , Ranjan Sharma

Interested in the collapse of a radiating star, we study the temporal evolution of a fluid with heat flux and bulk viscosity, including anisotropic pressure. As a starting point, we adopt an initial configuration that satisfies the…

General Relativity and Quantum Cosmology · Physics 2018-11-27 L. S. M. Veneroni , M. F. A. da Silva