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Related papers: On estimating angular momenta of infalling protost…

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We study the formation, evolution and collapse of dense cores by tracking structures in a magnetohydrodynamic simulation of a star-forming cloud. We identify cores using the dendrogram algorithm and utilize machine learning techniques,…

To understand the formation of stars from clouds of molecular gas, one essentially needs to know two things: What gas collapses, and how long it takes to do so. We address these questions by embedding pseudo-Lagrangian tracer particles in…

Astrophysics of Galaxies · Physics 2022-10-12 David C. Collins , Dan K. Le , Luz L. Jimenez Vela

Understanding the collapse of dense molecular cloud cores to stellar densities and the subsequent evolution of the protostar is of importance to model the feedback effects such an object has on its surrounding environment, as well as…

Solar and Stellar Astrophysics · Physics 2023-12-06 Adnan Ali Ahmad , Matthias González , Patrick Hennebelle , Benoît Commerçon

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

Observations reveal concentrations of molecular line emission on the sky, called ``clumps,'' in dense, star-forming molecular clouds. These clumps are believed to be the eventual sites of star formation. We study the three-dimensional…

Astrophysics · Physics 2009-11-07 C. F. Gammie , Y. -T. Lin , J. M. Stone , E. C. Ostriker

We present a detailed analysis comparing the velocity fields in molecular clouds and the atomic gas that surrounds them in order to address the origin of the gradients. To that end, we present first-moment intensity-weighted velocity maps…

Astrophysics of Galaxies · Physics 2015-05-27 N. Imara , L. Blitz

The angular momentum of molecular cloud cores plays a key role in the star formation process. However, the evolution of the angular momentum of molecular cloud cores formed in magnetized molecular filaments is still unclear. In this paper,…

Astrophysics of Galaxies · Physics 2023-12-29 Yoshiaki Misugi , Shu-ichiro Inutsuka , Doris Arzoumanian , Yusuke Tsukamoto

Continuum observations of molecular clouds have revealed a surprising amount of substructure in the form of filaments of a few pc length and cores of ~0.1 pc diameter. Understanding the evolution of these substructures towards star…

Solar and Stellar Astrophysics · Physics 2018-10-17 James Di Francesco , Jared Keown , Rachel Friesen , Tyler Bourke , Paola Caselli

In star forming regions, we can observe different evolutionary stages of various objects and phenomena such as molecular clouds, protostellar jets and outflows, circumstellar disks, and protostars. However, it is difficult to directly…

Solar and Stellar Astrophysics · Physics 2015-05-19 Masahiro N. Machida

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

In order to understand the origin of observed molecular cloud properties, it is critical to understand how clouds interact with their environments during their formation, growth, and collapse. It has been suggested that accretion-driven…

Astrophysics of Galaxies · Physics 2018-12-21 Juan C. Ibáñez-Mejía , Mordecai-Mark Mac Low , Ralf S. Klessen , Christian Baczynski

All molecular clouds are observed to be turbulent, but the origin, means of sustenance, and evolution of the turbulence remain debated. One possibility is that stellar feedback injects enough energy into the cloud to drive observed motions…

Astrophysics of Galaxies · Physics 2016-12-28 Ryan D. Boyden , Eric W. Koch , Erik W. Rosolowsky , Stella S. R. Offner

The evolution of collapsing metal free protostellar clouds is investigated for various masses and initial conditions. We perform hydrodynamical calculations for spherically symmetric clouds taking account of radiative transfer of the…

Astrophysics · Physics 2016-08-30 Kazuyuki Omukai , Ryoichi Nishi

Dense core collisions, previously regarded as minor in star formation, are proposed to play a significant role in structure formation around protostellar envelopes and binary formation. Using archival data of nearby star-forming regions, we…

Astrophysics of Galaxies · Physics 2024-02-20 Yuta Yano , Fumitaka Nakamura , Shinichi W. Kinoshita

We examine the conditions under which binary and multiple stars may form out of turbulent molecular cloud cores using high resolution 3-D, adaptive mesh refinement (AMR) hydrodynamics (Truelove et al., 1997, 1998; Klein, 1999). We argue…

Astrophysics · Physics 2007-05-23 R. I Klein , R. T. Fisher , C. F. McKee

The theory of how low mass stars form from the collapse of a dense molecular cloud core has been well-established for decades. Thanks to significant progress in computing and numerical modelling, more physical models have been developed and…

Solar and Stellar Astrophysics · Physics 2024-01-05 Alison K. Young

We performed sub-parsec (~0.06pc) scale simulations of two idealised molecular clouds with different masses undergoing a collision. Gas clumps with density greater than 1e-20 g/cm3 (0.3e4 cm-3) were identified as pre-stellar cores and…

Astrophysics of Galaxies · Physics 2015-06-22 Ken Takahira , Elizabeth J. Tasker , Asao Habe

We discuss problems with some observational estimates indicating long protostellar core lifetimes and large stellar age spreads in molecular clouds. We also point out some additional observational constraints which suggest that protostellar…

Astrophysics · Physics 2007-05-23 Javier Ballesteros-Paredes , Lee Hartmann

We performed sub-parsec ($\sim$ 0.014 pc) scale simulations of cloud-cloud collisions of two idealized turbulent molecular clouds (MCs) with different masses in the range of $0.76 - 2.67 \times 10^4$M$_{\odot}$ and with collision speeds of…

Astrophysics of Galaxies · Physics 2018-02-15 Ken Takahira , Kazuhiro Shima , Elizabeth J. Tasker , Asao Habe

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