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Recent observational and theoretical investigations have emphasised the importance of filamentary networks within molecular clouds as sites of star formation. Since such environments are more complex than those of isolated cores, it is…

Solar and Stellar Astrophysics · Physics 2014-08-29 Roxana-Adela Chira , Rowan J. Smith , Ralf S. Klessen , Amelia M. Stutz , Rahul Shetty

Filaments are a key step on the path that leads from molecular clouds to star formation. However, their characteristics are heavily debated, and the exact processes that lead to their formation and fragmentation into dense cores still…

Under the assumptions that molecular clouds are nearly spatially and temporally isothermal and that the density peaks (``cores'') within them are formed by turbulent fluctuations, we argue that cores cannot reach a hydrostatic (or…

We present the results of smoothed particle hydrodynamic simulations investigating the evolution and fragmentation of filaments that are accreting from a turbulent medium. We show that the presence of turbulence, and the resulting…

Astrophysics of Galaxies · Physics 2017-04-19 S. D. Clarke , A. P. Whitworth , A. Duarte-Cabral , D. A. Hubber

We perform numerical magnetohydrodynamic (MHD) simulations of the gravitational collapse and fragmentation of a cylindrical molecular cloud with the help of the FLASH code. The cloud collapses rapidly along its radius without any signs of…

Astrophysics of Galaxies · Physics 2024-05-15 I. M. Sultanov , S. A. Khaibrakhmanov

The collapse of weakly turbulent prestellar cores is a critical stage in the process of star formation. Being highly non-linear and stochastic, the outcome of collapse can only be explored theoretically by performing large ensembles of…

Astrophysics of Galaxies · Physics 2015-05-30 S. Walch , A. P. Whitworth , P. Girichidis

We investigate the collapse and fragmentation of low-mass, trans-sonically turbulent prestellar cores, using SPH simulations. The initial conditions are slightly supercritical Bonnor-Ebert spheres, all with the same density profile, the…

Solar and Stellar Astrophysics · Physics 2015-05-13 S. Walch , T. Naab , A. Burkert , A. Whitworth , M. Gritschneder

We show that hydrodynamic turbulent cloud simulations naturally produce large filaments made up of a network of smaller and coherent sub-filaments. Such simulations resemble observations of filaments and fibres in nearby molecular clouds.…

Astrophysics of Galaxies · Physics 2015-12-09 Rowan J. Smith , Simon C. O. Glover , Ralf S. Klessen , Gary A. Fuller

In this paper, we present the results of 3-dimensional collapse simulations of rotating stars for a range of stellar progenitors. We find that for the fastest spinning stars, rotation does indeed modify the convection above the…

Astrophysics · Physics 2009-11-10 C. L. Fryer , M. S. Warren

Filamentary structures are closely associated with star-forming cores, but their detailed physical connections are still not clear. We studied the dense gas in the region of OMC-3 MMS-7 in Orion A molecular cloud using the molecular lines…

Astrophysics of Galaxies · Physics 2021-07-07 Zhiyuan Ren , Lei Zhu , Hui Shi , Nannan Yue , Di Li , Qizhou Zhang , Diego Mardones , Jingwen Wu , Sihan Jiao , Shu Liu , Gan Luo , Jinjin Xie , Chao Zhang , Xuefang Xu

Context. Low-mass star-forming cores differ from their surrounding molecular cloud in turbulence, shape, and density structure. Aims. We aim to understand how dense cores form out of the less dense cloud material by studying the connection…

Astrophysics of Galaxies · Physics 2015-05-28 A. Hacar , M. Tafalla

Almost all young stars are found in multiple systems. This suggests that protostellar cores almost always fragment into multiple objects. The observed properties of multiple systems such as their separation distribution and mass ratios…

Astrophysics · Physics 2007-05-23 S. P. Goodwin , P. Kroupa , A. Goodman , A. Burkert

We calculate the evolution of cloud cores embedded in different envelopes to investigate environmental effects on the mass accretion rate onto protostars. As the initial state, we neglect the magnetic field and cloud rotation, and adopt…

Solar and Stellar Astrophysics · Physics 2023-01-11 Shingo Nozaki , Masahiro N. Machida

Using numerical simulations, we investigate the gravitational evolution of filamentary molecular cloud structures and their condensation into dense protostellar cores. One possible process is the so called 'edge effect', the pile-up of…

Astrophysics of Galaxies · Physics 2023-04-06 Elena Hoemann , Stefan Heigl , Andreas Burkert

Stars form when filaments and dense cores in molecular clouds fragment and collapse due to self-gravity. In the most basic analyses of gravitational stability, the competition between self-gravity and thermal pressure sets the critical…

Astrophysics of Galaxies · Physics 2016-06-15 Young Min Seo , Andrew N. Youdin

Context: The formation of high-mass star-forming regions from their parental gas cloud and the subsequent fragmentation processes lie at the heart of star formation research. Aims: We aim to study the dynamical and fragmentation properties…

Star formation is intimately linked to the dynamical evolution of molecular clouds. Turbulent fragmentation determines where and when protostellar cores form, and how they contract and grow in mass via accretion from the surrounding cloud…

Astrophysics · Physics 2007-05-23 Ralf Klessen

Motivated by recent observational searches of sub-structure in starless molecular cloud cores, we investigate the evolution of density perturbations on scales smaller than the Jeans length embedded in contracting isothermal clouds, adopting…

Solar and Stellar Astrophysics · Physics 2017-12-20 C. Toci , D. Galli , A. Verdini , L. Del Zanna , S. Landi

Observations are revealing the ubiquity of filamentary structures in molecular clouds. As cores are often embedded in filaments, it is important to understand how line profiles from such systems differ from those of isolated cores. We…

Astrophysics of Galaxies · Physics 2015-06-04 Rowan J. Smith , Rahul Shetty , Amelia M. Stutz , Ralf S. Klessen

Filamentary molecular clouds are recognized as primary sites for the formation of stars. Specifically, regions characterized by the overlapping point of multiple filaments, known as hub regions, often associated with active star formation.…

Astrophysics of Galaxies · Physics 2024-08-19 Raiga Kashiwagi , Kazunari Iwasaki , Kohji Tomisaka