scholarly journals Physical Processes in Massive Star Formation

1986 ◽  
Vol 116 ◽  
pp. 301-315
Author(s):  
Joseph Silk
Keyword(s):  
Star Formation ◽  
Molecular Clouds ◽  
Massive Star ◽  
Hii Regions ◽  
Stellar Mass ◽  
Giant Molecular Clouds ◽  
Physical Processes ◽  
Massive Star Formation ◽  
The Imf

The gravitational fragmentation theory of star formation is reviewed. Theoretical arguments are presented which suggest that the lower stellar mass cut-off to the IMF in giant HII regions may be as high as 10 M⊙. Mechanisms for bimodal star formation are described in the context of a coagulation model for formation of the giant molecular clouds, and application is made to starbursting galaxies.

scholarly journals The elephant in the room: the importance of the details of massive star formation in molecular clouds

2019 ◽  
Vol 488 (2) ◽  
pp. 2970-2975 ◽  
Author(s):  
Michael Y Grudić ◽  
Philip F Hopkins
Keyword(s):  
Star Formation ◽  
Molecular Clouds ◽  
Massive Star ◽  
Initial Conditions ◽  
Mass Function ◽  
Initial Mass Function ◽  
Giant Molecular Clouds ◽  
Massive Star Formation ◽  
Average Mass ◽  
Sampling Schemes

Abstract Most simulations of galaxies and massive giant molecular clouds (GMCs) cannot explicitly resolve the formation (or predict the main-sequence masses) of individual stars. So they must use some prescription for the amount of feedback from an assumed population of massive stars (e.g. sampling the initial mass function, IMF). We perform a methods study of simulations of a star-forming GMC with stellar feedback from UV radiation, varying only the prescription for determining the luminosity of each stellar mass element formed (according to different IMF sampling schemes). We show that different prescriptions can lead to widely varying (factor of ∼3) star formation efficiencies (on GMC scales) even though the average mass-to-light ratios agree. Discreteness of sources is important: radiative feedback from fewer, more-luminous sources has a greater effect for a given total luminosity. These differences can dominate over other, more widely recognized differences between similar literature GMC-scale studies (e.g. numerical methods, cloud initial conditions, presence of magnetic fields). Moreover the differences in these methods are not purely numerical: some make different implicit assumptions about the nature of massive star formation, and this remains deeply uncertain in star formation theory.

scholarly journals GIANT MOLECULAR CLOUDS AND MASSIVE STAR FORMATION IN THE SOUTHERN MILKY WAY

2014 ◽  
Vol 212 (1) ◽  
pp. 2 ◽  
Author(s):  
P. García ◽  
L. Bronfman ◽  
Lars-Åke Nyman ◽  
T. M. Dame ◽  
A. Luna
Keyword(s):  
Star Formation ◽  
Molecular Clouds ◽  
Massive Star ◽  
Milky Way ◽  
Giant Molecular Clouds ◽  
Massive Star Formation

scholarly journals THE LOCATION, CLUSTERING, AND PROPAGATION OF MASSIVE STAR FORMATION IN GIANT MOLECULAR CLOUDS

2016 ◽  
Vol 832 (1) ◽  
pp. 43 ◽  
Author(s):  
Bram B. Ochsendorf ◽  
Margaret Meixner ◽  
Jérémy Chastenet ◽  
Alexander G. G. M. Tielens ◽  
Julia Roman-Duval
Keyword(s):  
Star Formation ◽  
Molecular Clouds ◽  
Massive Star ◽  
Giant Molecular Clouds ◽  
Massive Star Formation ◽  
Location Clustering

scholarly journals What Sets the Massive Star Formation Rates and Efficiencies of Giant Molecular Clouds?

2017 ◽  
Vol 841 (2) ◽  
pp. 109 ◽  
Author(s):  
Bram B. Ochsendorf ◽  
Margaret Meixner ◽  
Julia Roman-Duval ◽  
Mubdi Rahman ◽  
Neal J. Evans
Keyword(s):  
Star Formation ◽  
Molecular Clouds ◽  
Massive Star ◽  
Giant Molecular Clouds ◽  
Massive Star Formation

Twinkle little stars: Massive stars are quenched in strong magnetic fields

2018 ◽  
Vol 14 (A30) ◽  
pp. 118-118
Author(s):  
Fatemeh S. Tabatabaei ◽  
M. Almudena Prieto ◽  
Juan A. Fernández-Ontiveros
Keyword(s):  
Star Formation ◽  
Magnetic Fields ◽  
Molecular Clouds ◽  
Massive Star ◽  
Massive Stars ◽  
Radio Continuum ◽  
Small Scale ◽  
Massive Star Formation ◽  
Low Mass ◽  
Formation Efficiency

AbstractThe role of the magnetic fields in the formation and quenching of stars with different mass is unknown. We studied the energy balance and the star formation efficiency in a sample of molecular clouds in the central kpc region of NGC 1097, known to be highly magnetized. Combining the full polarization VLA/radio continuum observations with the HST/Hα, Paα and the SMA/CO lines observations, we separated the thermal and non-thermal synchrotron emission and compared the magnetic, turbulent, and thermal pressures. Most of the molecular clouds are magnetically supported against gravitational collapse needed to form cores of massive stars. The massive star formation efficiency of the clouds also drops with the magnetic field strength, while it is uncorrelated with turbulence (Tabatabaei et al. 2018). The inefficiency of the massive star formation and the low-mass stellar population in the center of NGC 1097 can be explained in the following steps: I) Magnetic fields supporting the molecular clouds prevent the collapse of gas to densities needed to form massive stars. II) These clouds can then be fragmented into smaller pieces due to e.g., stellar feedback, non-linear perturbations and instabilities leading to local, small-scale diffusion of the magnetic fields. III) Self-gravity overcomes and the smaller clouds seed the cores of the low-mass stars.

scholarly journals Massive star formation in 100,000 years from turbulent and pressurized molecular clouds

Nature ◽  
2002 ◽  
Vol 416 (6876) ◽  
pp. 59-61 ◽  
Author(s):  
Christopher F. McKee ◽  
Jonathan C. Tan
Keyword(s):  
Star Formation ◽  
Molecular Clouds ◽  
Massive Star ◽  
Massive Star Formation

scholarly journals Dense molecular clouds and associated star formation in the Magellanic Clouds

2006 ◽  
Vol 2 (S237) ◽  
pp. 40-46
Author(s):  
Mónica Rubio
Keyword(s):  
Star Formation ◽  
Uv Radiation ◽  
Molecular Clouds ◽  
Massive Star ◽  
Dust Emission ◽  
Young Stellar Objects ◽  
Continuum Emission ◽  
Giant Molecular Clouds ◽  
Stellar Objects ◽  
Ir Sources

AbstractMultiwavelengths studies of massive star formation regions in the LMC and SMC reveal that a second generation of stars is being formed in dense molecular clouds located in the surroundings of the massive clusters. These dense molecular clouds have survived the action of massive star UV radiation fields and winds and they appear as compact dense H2 knots in regions of weak CO emission. Alternatively, we have found that large molecular clouds, probably remnants of the parental giant molecular clouds where the first generation of stars were formed, are suffering the interaction of the winds and UV radiation field in their surfaces in the direction of the central massive cluster or massive stars. These molecular regions show 1.2 mm continuum emission form cold dust and they show embedded IR sources as determined from deep ground base JHKs imaging. The distribution of young IR sources as determined from their Mid IR colors obtained by SPITZER concentrate in the maxima of CO and dust emission. IR spectroscopy of the embedded sources with high IR excess confirm their nature as massive young stellar objects (MYSO's). Our results are suggestive of contagious star formation where triggering and induced star formation could be taking place.

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