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Motivated by recent observations which detect an outer boundary for starless cores, and evidence for time-dependent mass accretion in the Class 0 and Class I protostellar phases, we reexamine the case of spherical isothermal collapse in the…

Astrophysics · Physics 2009-11-10 E. I. Vorobyov , Shantanu Basu

The collapse of slowly rotating molecular cloud cores threaded by magnetic fields is investigated by high-resolution numerical simulation. Outflow formation in the collapsing cloud cores is also followed. In the models examined, the cloud…

Astrophysics · Physics 2009-11-10 Tomoaki Matsumoto , Kohji Tomisaka

Angular momentum plays a crucial role in the formation of stars and planets. It has long been noticed that parcels of gas in molecular clouds need to reduce their specific angular momentum by 6 to 7 orders of magnitude to participate in the…

Astrophysics of Galaxies · Physics 2015-06-15 Arnaud Belloche

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

We present results from the first three-dimensional radiation hydrodynamical calculations to follow the collapse of a molecular cloud core beyond the formation of the stellar core. We find the energy released by the formation of the stellar…

Solar and Stellar Astrophysics · Physics 2015-05-18 Matthew R. Bate

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 employ the three-dimensional magnetohydrodynamic simulation including ambipolar diffusion to study the gravitationally-driven fragmentation of subcritical molecular clouds, in which the gravitational fragmentation is stabilized as long…

Solar and Stellar Astrophysics · Physics 2015-05-20 Takahiro Kudoh , Shantanu Basu

Theoretical studies of collapsing clouds have found that even a relatively weak magnetic field (B) may prevent the formation of disks and their fragmentation. However, most previous studies have been limited to cases where B and the…

Solar and Stellar Astrophysics · Physics 2015-06-04 Marc Joos , Patrick Hennebelle , Andrea Ciardi

All gravitationally bound clusters expand, due to both gas loss from their most massive members and binary heating. All are eventually disrupted tidally, either by passing molecular clouds or the gravitational potential of their host…

Astrophysics of Galaxies · Physics 2014-07-22 Ryan M. O'Leary , Steven W. Stahler , Chung-Pei Ma

We investigate the origin of the observed scaling $j\sim R^{3/2}$ between the specific angular momentum $j$ and the radius $R$ of molecular clouds (MCs) and their their substructures, and of the observed near independence of $\beta$, the…

Astrophysics of Galaxies · Physics 2022-02-02 G. Arroyo-Chávez , E. Vázquez-Semadeni

We discuss the lifetimes and evolution of dense cores formed as turbulent density fluctuations in magnetized, isothermal molecular clouds. We consider numerical simulations in which we measure the cores' magnetic criticality and Jeans…

Astrophysics · Physics 2007-05-23 E. Vazquez-Semadeni , J. Kim , M. Shadmehri , J. Ballesteros-Paredes

We report the existence of hydrostatic equilibrium states for a composite body made of two rigidly rotating, homogeneous layers bounded by spheroidal surfaces, where the core has a prolate shape. These new configurations require an oblate…

Earth and Planetary Astrophysics · Physics 2024-10-21 Clément Staelen , Jean-Marc Huré , Anaïs Meunier , Pauline Noé

We study numerically the collapse of rotating, magnetized molecular cloud cores, focusing on rotation and magnetic braking during the main accretion phase of isolated star formation. Motivated by previous numerical work and analytic…

Astrophysics · Physics 2009-11-10 A. Allen , Z. Y. Li , F. H. Shu

The observed properties of young star clusters, such as the core radius and luminosity profile, change rapidly during the early evolution of the clusters. Here we present observations of 6 young clusters in M51 where we derive their sizes…

Astrophysics · Physics 2009-11-13 N. Bastian , M. Gieles , S. P. Goodwin , G. Trancho , L. J. Smith , I. Konstantopoulos , Yu. Efremov

A physical model and two-dimensional numerical method for computing the evolution and spectra of protostellar clouds are described. The physical model is based on a system of magneto-gasdynamical equations, including ohmic and ambipolar…

Instrumentation and Methods for Astrophysics · Physics 2015-05-13 A. G. Zhilkin , Ya. N. Pavlyuchenkov , S. N. Zamozdra

We conduct a systematic examination of the properties of models for chemically homogeneous, differentially rotating, main-sequence stars of mass 1-2 M_sun. The models were constructed using a code based on a reformulation of the…

Astrophysics · Physics 2009-06-23 K. B. MacGregor , Stephen Jackson , Andrew Skumanich , T. S. Metcalfe

Gravitational collapse of the cylindrical elongated cloud is studied by numerical magnetohydrodynamical simulations. In the infinitely long cloud in hydrostatic configuration, small perturbations grow by the gravitational instability. The…

Astrophysics · Physics 2009-10-22 Kohji Tomisaka

[abridged] We investigate the velocity structure of protostellar cores that result from non-magnetic numerical models of the gravoturbulent fragmentation of molecular cloud material. A large fraction of the cores analyzed are ``quiescent'',…

We extend our earlier work on ambipolar diffusion induced formation of protostellar cores in isothermal sheet-like magnetic interstellar clouds, by studying nonaxisymmetric collapse for the physically interesting regime of magnetically…

Astrophysics · Physics 2009-11-10 Shantanu Basu , Glenn E. Ciolek

We use 3mm multi-line and continuum CARMA observations towards the first hydrostatic core (FHSC) candidate L1451-mm to characterize the envelope kinematics at 1000 AU scales and investigate its evolutionary state. We detect evidence of…

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