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We numerically investigate the effect of feedback from the ionizing radiation heating from massive stars on the evolution of giant molecular clouds (GMCs) and their star formation efficiency (SFE). We find that the star-forming regions…

Astrophysics of Galaxies · Physics 2015-05-14 Enrique Vazquez-Semadeni , Pedro Colin , Gilberto C. Gomez , Alan Watson

(Abridged) We present a series of decaying turbulence simulations that represent a cluster-forming clump within a molecular cloud, investigating the role of magnetic fields on the formation of potential star-forming cores. We present an…

Astrophysics · Physics 2007-11-07 David A. Tilley , Ralph E. Pudritz

Stars form by gravoturbulent fragmentation of interstellar gas clouds. The supersonic turbulence ubiquitously observed in Galactic molecular gas generates strong density fluctuations with gravity taking over in the densest and most massive…

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…

The gravitational binding and star-forming properties of molecular clouds (MCs) in the Milky Way (MW) are estimated from CO cloud observations and from a model of pressure-bounded virial equilibrium (PVE). Two CO surveys are analyzed with…

Astrophysics of Galaxies · Physics 2025-08-11 Philip C. Myers , Mark Heyer , Ian W. Stephens , Simon Coudé , Nicole Karnath , Howard A. Smith

We study the formation of giant dense cloud complexes and of stars within them by means of SPH numerical simulations of the mildly supersonic collision of gas streams (``inflows'') in the warm neutral medium (WNM). The resulting…

We investigate the formation by accretion of massive primordial protostars in the range 10 to 300 Msun. The high accretion rate used in the models (4.4 x 10^{-3} Msun/yr) causes the structure and evolution to differ significantly from those…

Astrophysics · Physics 2009-11-07 K. Omukai , F. Palla

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

For a number of starless cores, self-absorbed molecular line and column density observations have implied the presence of large-amplitude oscillations. We examine the consequences of these oscillations on the evolution of the cores and the…

Solar and Stellar Astrophysics · Physics 2015-05-19 Avery E. Broderick , Eric Keto

The formation of stars and planetary systems is a complex phenomenon, which relies on the interplay of multiple physical processes. Nonetheless, it represents a crucial stage for our understanding of the Universe, and in particular of the…

Astrophysics of Galaxies · Physics 2022-01-05 Alessandro Lupi , Stefano Bovino , Tommaso Grassi

We describe results from a fully self-consistent three dimensional hydrodynamical simulation of the formation of one of the first stars in the Universe. Dark matter dominated pre-galactic objects form because of gravitational instability…

Astrophysics · Physics 2011-06-15 Tom Abel , Greg L. Bryan , Michael L. Norman

Chemical composition of the massive cores forming high-mass stars can put some constrains on the time scale of the massive star formation: sulphur chemistry is of specific interest due to its rapid evolution in warm gas and because the…

Solar and Stellar Astrophysics · Physics 2009-10-28 Fabrice Herpin , Matthieu Marseille , Valentine Wakelam , Sylvain Bontemps , D. C. Lis

Hydrodynamical simulations of star formation indicate that the motions of protostars through their natal molecular clouds may be crucial in determining the properties of stars through competitive accretion and dynamical interactions. Walsh,…

Astrophysics · Physics 2008-11-26 Ben A. Ayliffe , James C. Langdon , Howard S. Cohl , Matthew R. Bate

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

We formulate the problem of the late accretion phase of the evolution of an isothermal magnetic disk surrounding a forming star. The evolution is described by the six-fluid MHD equations, accounting for the presence of neutrals, atomic and…

Astrophysics · Physics 2009-11-10 Konstantinos Tassis , Telemachos Ch. Mouschovias

The results of spectral observations in the $\sim 84-92$ GHz frequency range of six objects in the southern sky containing dense cores and associated with regions of massive stars and star clusters formation are presented. The observations…

Astrophysics of Galaxies · Physics 2024-03-06 L. E. Pirogov , P. M. Zemlyanukha , E. M. Dombek , M. A. Voronkov

It is now a widely held view that, in their formation and early evolution, stars build up mass in bursts. The burst mode of star formation scenario proposes that the stars grow in mass via episodic accretion of fragments migrating from…

Solar and Stellar Astrophysics · Physics 2020-11-25 D. M. -A. Meyer , E. I. Vorobyov , V. G. Elbakyan , J. Eisloeffel , A. M. Sobolev , M. Stoehr

Context. Molecular Clouds (MCs) are the place where stars are formed and their feedback starts to take place, regulating the evolution of galaxies. Therefore, MCs represent the critical scale at which to study how ultra-violet (UV) photons…

Astrophysics of Galaxies · Physics 2025-03-12 Fabio Di Mascia , Andrea Pallottini , Laura Sommovigo , Davide Decataldo

In regions of star formation, protostars and newborn stars accrete mass from their natal clouds. These clouds are threaded by magnetic fields with a strength characterized by the plasma beta---the ratio of thermal and magnetic pressures.…

Astrophysics of Galaxies · Physics 2015-06-18 Aaron T. Lee , Andrew J. Cunningham , Christopher F. McKee , Richard I. Klein