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Related papers: Micro- and macroturbulence derived from 3D hydrody…

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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

We examine the physical parameters that affect the accumulation of gas in molecular clouds to high column densities where the formation of stars takes place. In particular, we analyze the dense gas mass fraction (DGMF) in a set of…

Astrophysics of Galaxies · Physics 2015-06-15 Jouni Kainulainen , Christoph Federrath , Thomas Henning

The numerical simulation of turbulence in stars has led to a rich set of possibilities regarding stellar pulsations, asteroseismology, thermonuclear yields, and formation of neutron stars and black holes. The breaking of symmetry by…

Solar and Stellar Astrophysics · Physics 2016-10-05 W. David Arnett , Casey Meakin

An important aspect of astrophysical MHD turbulence research is developing diagnostics to connect simulations with the observable universe. Turbulent systems are by definition structurally complex in all fluid variables (density, velocity,…

Astrophysics · Physics 2007-05-23 Eve C. Ostriker

We introduce and test an expression for calculating the variance of a physical field in three dimensions using only information contained in the two-dimensional projection of the field. The method is general but assumes statistical…

Astrophysics of Galaxies · Physics 2015-05-14 C. M. Brunt , C. Federrath , D. J. Price

During the recent years significant progress has been made in the modeling of red giant atmospheres with the aid of 3D hydrodynamical model atmosphere codes. In this contribution we provide an overview of selected results obtained in this…

Solar and Stellar Astrophysics · Physics 2013-05-16 A. Kucinskas , H. -G. Ludwig , M. Steffen , V. Dobrovolskas , J. Klevas , D. Prakapavicius , E. Caffau , P. Bonifacio

It is believed that turbulence may have a significant impact on star formation and the dynamics and evolution of the molecular clouds in which this occurs. It is also known that non-ideal magnetohydrodynamic effects influence the nature of…

Astrophysics of Galaxies · Physics 2015-06-05 T. P. Downes

A fundamental property of molecular clouds is that they are turbulent, but how this turbulence is generated and maintained is unknown. One possibility is that stars forming within the cloud regenerate turbulence via their outflows, winds…

Solar and Stellar Astrophysics · Physics 2018-10-17 Stella S. R. Offner , Yue Liu

We provide a brief overview of recent advances and outstanding issues in simulations of interstellar turbulence, including isothermal models for interior structure of molecular clouds and larger-scale multiphase models designed to simulate…

Astrophysics of Galaxies · Physics 2011-05-05 Alexei G. Kritsuk , Sergey D. Ustyugov , Michael L. Norman

We use detailed numerical simulations of the coupled chemical, thermal and dynamical evolution of the gas in a turbulent molecular cloud to study the usefulness of the [CI] 609 micron and 370 micron fine structure emission lines as tracers…

Astrophysics of Galaxies · Physics 2015-06-19 Simon C. O. Glover , Paul C. Clark , Milica Micic , Faviola Molina

We present an efficient technique to study the 1D evolution of instability-generated structure in winds of hot stars out to very large distances (more than 1000 stellar radii). This technique makes use of our previous finding that external…

Astrophysics · Physics 2009-11-10 M. C. Runacres , S. P. Owocki

Grids of stellar atmosphere models and associated synthetic spectra are numerical products which have a large impact in astronomy due to their ubiquitous application in the interpretation of radiation from individual stars and stellar…

Solar and Stellar Astrophysics · Physics 2009-09-02 H. -G. Ludwig , E. Caffau , M. Steffen , B. Freytag , P. Bonifacio , A. Kucinskas

I describe recent progress in terms of 3D hydrodynamical model atmospheres and 3D line formation and their applications to stellar abundance analyses of late-type stars. Such 3D studies remove the free parameters inherent in classical 1D…

Astrophysics · Physics 2007-05-23 Martin Asplund

In this contribution, we present the StaggerGrid, a collaborative project for the construction of a comprehensive grid of time-dependent, three-dimensional (3D), hydrodynamic model atmospheres of solar- and late-type stars with different…

Solar and Stellar Astrophysics · Physics 2015-05-30 Remo Collet , Zazralt Magic , Martin Asplund

We analyze a suite of thin sheet magnetohydrodynamical simulations based on the formulation of Basu, Ciolek, Dapp & Wurster. These simulations allow us to examine the observational consequences to a star-forming region of varying the input…

Solar and Stellar Astrophysics · Physics 2009-07-22 Helen Kirk , Doug Johnstone , Shantanu Basu

Broadening and asymmetry of spectral lines in slowly rotating late A-type stars provide evidence for high-amplitude convective motions. The properties of turbulence observed in the A-star atmospheres are not understood theoretically and…

Astrophysics · Physics 2015-06-24 O. Kochukhov , B. Freytag , N. Piskunov , M. Steffen

Astrophysical fluids, including interstellar and interplanetary medium, are magnetized and turbulent. Their appearance, evolution, and overall properties are determined by the magnetic turbulence that stirs it. We argue that examining…

Astrophysics · Physics 2009-11-13 A. Lazarian , A. Beresnyak , H. Yan , M. Opher , Y. Liu

We present an analytical model of the relation between the surface density of gas and star formation rate in galaxies and clouds, as a function of the presence of supersonic turbulence and the associated structure of the interstellar…

Cosmology and Nongalactic Astrophysics · Physics 2012-11-06 Florent Renaud , Katarina Kraljic , Frédéric Bournaud

Several topics in the theory of magnetized turbulence are reviewed with application to star formation and the interstellar medium. The density, pressure, and temperature distribution in a turbulent interstellar medium is described in…

Astrophysics · Physics 2007-05-23 Mordecai-Mark Mac Low

Macroturbulence, introduced as a fudge to reproduce the width and shape of stellar absorption lines, reflects gas motions in stellar atmospheres. While in cool stars, it is thought to be caused by convection zones immediately beneath the…

Solar and Stellar Astrophysics · Physics 2016-09-07 Luca Grassitelli , Luca Fossati , Norbert Langer , Sergio Simon-Diaz , Norberto Castro , Debashis Sanyal