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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 formulate the problem of the formation of magnetically supercritical cores in magnetically subcritical parent molecular clouds, and the subsequent collapse of the cores to high densities, past the detachment of ions from magnetic field…

Astrophysics · Physics 2011-02-11 Konstantinos Tassis , Telemachos Ch. Mouschovias

We demonstrate that the formation of collapsing cores in subcritical clouds is accelerated by nonlinear flows, by performing three-dimensional non-ideal MHD simulations. An initial random supersonic (and trans-Alfvenic) turbulent-like flow…

Astrophysics · Physics 2009-11-13 Takahiro Kudoh , Shantanu Basu

Magnetic diffusion plays a vital role in star formation. We trace its influence from interstellar cloud scales down to star-disk scales. On both scales, we find that magnetic diffusion can be significantly enhanced by the buildup of strong…

Solar and Stellar Astrophysics · Physics 2013-08-19 Shantanu Basu , Wolf B. Dapp

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

We discuss the effects of the magnetic field observed in molecular clouds on the process of star formation, concentrating on the phase of gravitational collapse of low-mass dense cores, cradles of sunlike stars. We summarize recent analytic…

Astrophysics of Galaxies · Physics 2015-06-23 Susana Lizano , Daniele Galli

We investigate the formation and evolution of giant molecular clouds (GMCs) by the collision of convergent warm neutral medium (WNM) streams in the interstellar medium, in the presence of magnetic fields and ambipolar diffusion (AD),…

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

In the standard picture of isolated star formation, dense ``starless'' cores are formed out of magnetic molecular clouds due to ambipolar diffusion. Under the simplest spherical geometry, I demonstrate that ``starless'' cores formed this…

Astrophysics · Physics 2009-10-31 Zhi-Yun Li

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

We summarize the current status of the turbulent model of star formation in turbulent molecular clouds. In this model, clouds, clumps and cores form a hierarchy of nested density fluctuations caused by the turbulence, and either collapse or…

Astrophysics · Physics 2007-05-23 Enrique Vazquez-Semadeni

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 investigate the physical properties of dense cores formed in turbulent, magnetized, parsec-scale clumps of molecular clouds, using three-dimensional numerical simulations that include protostellar outflow feedback. The dense cores are…

Solar and Stellar Astrophysics · Physics 2015-05-28 Fumitaka Nakamura , Zhi-Yun Li

We present a simple model of binary star formation based on the assumption that rotating prestellar cores collapse to form rings and these rings then fragment into protostars. We assume that each ring spawns a small number (N <= 6) of…

Astrophysics · Physics 2009-11-10 D. A. Hubber , A. P. Whitworth

Theoretically, stars have been formed from the collapse of cores in the molecular clouds. Historically, the core had been assumed as an singular isothermal sphere (SIS), and the collapse had been investigated by a self-similar manner. This…

Astrophysics of Galaxies · Physics 2015-05-19 Mohsen Nejad-Asghar

We present the results of eighteen magnetohydrodynamical calculations of the collapse of a molecular cloud core to form a protostar. Some calculations include radiative transfer in the flux-limited diffusion approximation while others…

Solar and Stellar Astrophysics · Physics 2018-04-11 Benjamin T. Lewis , Matthew R. Bate

Observations indicate that dense molecular filamentary clouds are sites of star formation. The filament width determines the most unstable scale for self-gravitational fragmentation and influences the stellar mass. Therefore, constraining…

Astrophysics of Galaxies · Physics 2025-05-09 Daisei Abe , Tsuyoshi Inoue , Shu-ichiro Inutsuka , Doris Arzoumanian

(Abridged) Context. Massive stars form in magnetized and turbulent environments, and are often located in stellar clusters. Their accretion mechanism, as well as the origin of their system's stellar multiplicity are poorly understood. Aims.…

Solar and Stellar Astrophysics · Physics 2021-08-11 R. Mignon-Risse , M. González , B. Commerçon , Joakim Rosdahl

We develop a detailed chemical model for the starless cores of strongly magnetized molecular clouds, with the ambipolar diffusion-driven dynamic evolution of the clouds coupled to the chemistry through ion abundances. We concentrate on two…

Astrophysics · Physics 2009-11-07 Zhi-Yun Li , V. I. Shematovich , D. S. Wiebe , B. M. Shustov

Supersonic isothermal turbulence establishes a network of transient dense shocks that sweep up material and have a density profile described by balance between ram pressure of the background fluid versus the magnetic and gas pressure…

Astrophysics of Galaxies · Physics 2018-08-08 Philip Mocz , Blakesley Burkhart