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We revisit the problem of the formation of dense protostellar cores due to ambipolar diffusion within magnetically supported molecular clouds, and derive an analytical expression for the core formation timescale. The resulting expression is…

Astrophysics · Physics 2009-10-31 Glenn E. Ciolek , Shantanu Basu

In our grid of multiphase chemical evolution models (Moll\'a & D\'iaz, 2005), star formation in the disk occurs in two steps: first, molecular gas forms, and then stars are created by cloud-cloud collisions or interactions of massive stars…

Astrophysics of Galaxies · Physics 2017-04-12 Mercedes Mollá , Ángeles I. Díaz , Yago Ascasibar , Brad K. Gibson

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

We investigate the formation and early evolution of star clusters assuming that they form from a turbulent starless clump of given mass bounded inside a parent self-gravitating molecular cloud characterized by a particular mass surface…

Astrophysics of Galaxies · Physics 2017-04-05 Juan P. Farias , Jonathan C. Tan , Sourav Chatterjee

Star formation occurs in hierarchical patterns in both space and time. Galaxies form large regions on the scale of the interstellar Jeans length and these large regions apparently fragment into giant molecular clouds and cloud cores in a…

Astrophysics of Galaxies · Physics 2015-05-27 Bruce G. Elmegreen

We present a catalogue of molecular cloud cores drawn from high latitude, medium opacity clouds, using the all-sky IRAS Sky Survey Atlas (ISSA) images at 60 and 100~$\mu$m. The typical column densities of the cores are $ N(H_2)\sim 3.8…

Astrophysics · Physics 2009-10-31 N. E. Jessop , D. Ward-Thompson

We investigate protostellar collapse of molecular cloud cores by numerical simulations, taking into account turbulence and magnetic fields. By using the adaptive mesh refinement technique, the collapse is followed over a wide dynamic range…

Solar and Stellar Astrophysics · Physics 2015-05-19 Tomoaki Matsumoto , Tomoyuki Hanawa

I describe the scenario of molecular cloud (MC) evolution that has emerged over the past decade or so. MCs can start out as cold atomic clouds formed by compressive motions in the warm neutral medium (WNM) of galaxies. Such motions can be…

Astrophysics of Galaxies · Physics 2010-09-22 Enrique Vazquez-Semadeni

We investigate general aspects of molecular line formation under conditions which are typical of prestellar cores. Focusing on simple linear molecules, we study formation of their rotational lines by radiative transfer simulations. We…

Astrophysics · Physics 2009-11-13 Ya. Pavlyuchenkov , D. Wiebe , B. Shustov , Th. Henning , R. Launhardt , D. Semenov

We investigate the dynamical evolution of star clusters during their formation, assuming that they are born from a turbulent starless clump of a given mass that is embedded within a parent self-gravitating molecular cloud characterized by a…

Astrophysics of Galaxies · Physics 2018-12-26 Juan P. Farias , Jonathan C. Tan , Sourav Chatterjee

Fragmentation process in a cylindrical magnetized cloud is studied with the nested grid method. The nested grid scheme use 15 levels of grids with different spatial resolution overlaid subsequently, which enables us to trace the evolution…

Astrophysics · Physics 2015-06-24 Kohji Tomisaka

Recent observations of young stellar systems with the Atacama Large Millimeter/submillimeter Array (ALMA) and the Karl G. Jansky Very Large Array (VLA) are helping to cement the idea that close companion stars form via fragmentation of a…

Solar and Stellar Astrophysics · Physics 2018-04-25 Leonardo Di G. Sigalotti , Fidel Cruz , Ruslan Gabbasov , Jaime Klapp , José Ramírez-Velasquez

We discuss the lifetimes and evolution of clumps and cores formed as turbulent density fluctuations in nearly isothermal molecular clouds. In the non-magnetic case, clumps are unlikely to reach a hydrostatic state, and instead are expected…

We investigate the triggering of star formation and the formation of stellar clusters in molecular clouds that form as the ISM passes through spiral shocks. The spiral shock compresses gas into $\sim$100 pc long main star formation ridge,…

Astrophysics of Galaxies · Physics 2017-10-13 R. Smilgys , I. A. Bonnell

The configuration and evolution of the magnetic field in star-forming cores are investigated in order to directly compare simulations and observations. We prepare four different initial clouds having different magnetic field strengths and…

Solar and Stellar Astrophysics · Physics 2015-06-11 Akimasa Kataoka , Masahiro N. Machida , Kohji Tomisaka

Most stars in the Galaxy are believed to be formed within star clusters from collapsing molecular clouds. However, the complete process of star formation, from the parent cloud to a gas-free star cluster, is still poorly understood. We…

Astrophysics of Galaxies · Physics 2017-10-23 Elena Gavagnin , Andreas Bleuler , Joakim Rosdahl , Romain Teyssier

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

We present results from an extensive set of simulations of gravitational fragmentation in the presence of magnetic fields and ambipolar diffusion. The average fragmentation spacing in the nonlinear phase of evolution is in excellent…

Astrophysics · Physics 2008-12-18 Shantanu Basu , Glenn E. Ciolek , James Wurster

We present an analysis of star-forming gas cores in an SPH simulation of a Giant Molecular Cloud. We identify cores using their deep potential wells. This yields a smoother distribution with clearer boundaries than density. Additionally,…

Astrophysics of Galaxies · Physics 2015-05-13 Rowan J. Smith , Paul C. Clark , Ian A. Bonnell

Using hydrodynamic simulations we investigate the time evolution and fragmentation of regions within molecular clouds which have lost their turbulent support leading to gravitational contraction. The initial density distributions are…

Astrophysics · Physics 2009-10-31 Ralf Klessen , Andreas Burkert
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