On the Role of Massive Stars in the Support and Destruction of Giant Molecular Clouds

2002 ◽  
Vol 566 (1) ◽  
pp. 302-314 ◽  
Author(s):  
Christopher D. Matzner
Keyword(s):  
Molecular Clouds ◽  
Massive Stars ◽  
Giant Molecular Clouds

scholarly journals The role of galactic dynamics in shaping the physical properties of giant molecular clouds in Milky Way-like galaxies

2020 ◽  
Vol 498 (1) ◽  
pp. 385-429 ◽  
Author(s):  
Sarah M R Jeffreson ◽  
J M Diederik Kruijssen ◽  
Benjamin W Keller ◽  
Mélanie Chevance ◽  
Simon C O Glover
Keyword(s):  
Molecular Clouds ◽  
Large Scale ◽  
Milky Way ◽  
Gravitational Instability ◽  
Formation Rate ◽  
Tangential Velocity ◽  
Galactic Rotation ◽  
H Ii Regions ◽  
Giant Molecular Clouds

ABSTRACT We examine the role of the large-scale galactic-dynamical environment in setting the properties of giant molecular clouds in Milky Way-like galaxies. We perform three high-resolution simulations of Milky Way-like discs with the moving-mesh hydrodynamics code arepo, yielding a statistical sample of ${\sim}80\, 000$ giant molecular clouds and ${\sim}55\, 000$ H i clouds. We account for the self-gravity of the gas, momentum, and thermal energy injection from supernovae and H ii regions, mass injection from stellar winds, and the non-equilibrium chemistry of hydrogen, carbon, and oxygen. By varying the external gravitational potential, we probe galactic-dynamical environments spanning an order of magnitude in the orbital angular velocity, gravitational stability, mid-plane pressure, and the gradient of the galactic rotation curve. The simulated molecular clouds are highly overdense (∼100×) and overpressured (∼25×) relative to the ambient interstellar medium. Their gravoturbulent and star-forming properties are decoupled from the dynamics of the galactic mid-plane, so that the kpc-scale star formation rate surface density is related only to the number of molecular clouds per unit area of the galactic mid-plane. Despite this, the clouds display clear, statistically significant correlations of their rotational properties with the rates of galactic shearing and gravitational free-fall. We find that galactic rotation and gravitational instability can influence their elongation, angular momenta, and tangential velocity dispersions. The lower pressures and densities of the H i clouds allow for a greater range of significant dynamical correlations, mirroring the rotational properties of the molecular clouds, while also displaying a coupling of their gravitational and turbulent properties to the galactic-dynamical environment.

scholarly journals Physical conditions of star forming sites in the S247/252 molecular complex

1991 ◽  
Vol 147 ◽  
pp. 443-444
Author(s):  
C. Koempe ◽  
G. Joncas ◽  
J.G.A. Wouterloot ◽  
H. Meyerdierks
Keyword(s):  
Star Formation ◽  
Molecular Complex ◽  
Molecular Clouds ◽  
Massive Stars ◽  
Giant Molecular Clouds ◽  
Star Forming ◽  
Physical Conditions ◽  
Input Parameters

By now, it is well established that massive stars form in giant molecular clouds. Numerous studies have shown that star formation, instead of being spread uniformly throughout molecular clouds, occurs in dense condensations located within these clouds. The physical conditions in these condensations are therefore critical input parameters for any theory of star formation.

scholarly journals The Role of Magnetic Fields in Star Formation

2013 ◽  
Vol 9 (S302) ◽  
pp. 10-20 ◽  
Author(s):  
Ralph E. Pudritz ◽  
Mikhail Klassen ◽  
Helen Kirk ◽  
Daniel Seifried ◽  
Robi Banerjee
Keyword(s):  
Angular Momentum ◽  
Star Formation ◽  
Magnetic Fields ◽  
Molecular Clouds ◽  
Star Clusters ◽  
Young Stars ◽  
Giant Molecular Clouds ◽  
Jets And Outflows ◽  
Radiation Fields

AbstractStars are born in turbulent, magnetized filamentary molecular clouds, typically as members of star clusters. Several remarkable technical advances enable observations of magnetic structure and field strengths across many physical scales, from galactic scales on which giant molecular clouds (GMCs) are assembled, down to the surfaces of magnetized accreting young stars. These are shedding new light on the role of magnetic fields in star formation. Magnetic fields affect the gravitational fragmentation and formation of filamentary molecular clouds, the formation and fragmentation of magnetized disks, and finally to the shedding of excess angular momentum in jets and outflows from both the disks and young stars. Magnetic fields play a particularly important role in angular momentum transport on all of these scales. Numerical simulations have provided an important tool for tracking the complex process of the collapse and evolution of protostellar gas since several competing physical processes are at play - turbulence, gravity, MHD, and radiation fields. This paper focuses on the role of magnetic fields in three crucial regimes of star formation: the formation of star clusters emphasizing fragmentation, disk formation and the origin of early jets and outflows, to processes that control the spin evolution of young stars.

scholarly journals THE GLOBAL EVOLUTION OF GIANT MOLECULAR CLOUDS. II. THE ROLE OF ACCRETION

2011 ◽  
Vol 738 (1) ◽  
pp. 101 ◽  
Author(s):  
Nathan J. Goldbaum ◽  
Mark R. Krumholz ◽  
Christopher D. Matzner ◽  
Christopher F. McKee
Keyword(s):  
Molecular Clouds ◽  
Giant Molecular Clouds ◽  
Global Evolution

scholarly journals Structure and Conditions in Massive Star Forming Giant Molecular Clouds

2002 ◽  
Vol 12 ◽  
pp. 140-142
Author(s):  
Jonathan Williams
Keyword(s):  
Star Formation ◽  
Molecular Clouds ◽  
Massive Star ◽  
Massive Stars ◽  
The Other ◽  
Giant Molecular Clouds ◽  
Star Forming ◽  
Millimeter Wavelength ◽  
Formation And Evolution ◽  
Self Similar

AbstractMassive stars form in clusters within self-gravitating molecular clouds. The size scale of these clusters is sufficiently large that non-thermal, or turbulent, motions of the gas must be taken into account when considering their formation. Millimeter wavelength radio observations of the gas and dust in these clouds reveal a complex, self-similar structure that reflects the turbulent nature of the gas. Differences are seen, however, towards dense bound cores in proto-clusters. Examination of the kinematics of gas around such cores suggests that dissipation of turbulence may be the first step in the star formation process. Newly formed stars, on the other hand, replenish turbulence through their winds and outflows. In this way, star formation may be self-regulated. Observations and simulations are beginning to demonstrate the key role that cloud turbulence plays in the formation and evolution of stellar groups.

scholarly journals Simulating the chemistry and dynamics of molecular clouds

2009 ◽  
Vol 5 (H15) ◽  
pp. 405-405
Author(s):  
S. C. O. Glover ◽  
C. Federrath ◽  
M.-M. Mac Low ◽  
R. S. Klessen
Keyword(s):  
Molecular Clouds ◽  
Chemical Structure ◽  
Three Dimensional ◽  
Dynamical Evolution ◽  
Giant Molecular Clouds ◽  
Interstellar Gas ◽  
Density Inhomogeneities ◽  
First Time ◽  
Three Dimensional Simulations

AbstractWe have performed high-resolution three-dimensional simulations of turbulent interstellar gas that for the first time self-consistently follow its coupled thermal, chemical and dynamical evolution. Our simulations have allowed us to quantify the formation timescales for the most important molecules found in giant molecular clouds (H2, CO), as well as their spatial distribution within the clouds. Our results are consistent with models in which molecular clouds form quickly, within 1–2 turbulent crossing times, and emphasize the crucial role of density inhomogeneities in determining the chemical structure of the clouds.

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