Discussion session on star formation, molecular clouds and the interstellar medium

1994 ◽  
Vol 217 (1-2) ◽  
pp. 227-230
Author(s):  
Karen M. Strom ◽  
Lennart Nordh ◽  
Eli Dwek
Keyword(s):  
Star Formation ◽  
Interstellar Medium ◽  
Molecular Clouds ◽  
Discussion Session

scholarly journals Symposium Summary: Fragmentation and Star Formation in Molecular Clouds

1991 ◽  
Vol 147 ◽  
pp. 379-386
Author(s):  
A. E. Glassgold
Keyword(s):  
Star Formation ◽  
Interstellar Medium ◽  
Molecular Clouds ◽  
Substantial Progress ◽  
Made In ◽  
Easy Solution

This Symposium on fragmentation and star formation has dealt with the heart of the study of molecular clouds, which is how they form stars. This problem is one of the most profound and challenging problems in all of astrophysics. The complexity of the interstellar medium adds to its difficulty and we cannot expect a quick and easy solution. Nonetheless, the reports presented at this Symposium indicate that substantial progress is being made in this field.

scholarly journals Relations Between Star Formation and the Interstellar Medium

1998 ◽  
Vol 179 ◽  
pp. 165-171 ◽  
Author(s):  
Y. Fukui ◽  
Y. Yonekura
Keyword(s):  
Star Formation ◽  
Interstellar Medium ◽  
Formation Process ◽  
Molecular Clouds ◽  
Future Prospects

We review observational results concerning star formation and dense molecular clouds, the interstellar medium most relevant to star-formation process, as well as future prospects.

Molecular Clouds

1977 ◽  
Vol 75 ◽  
pp. 37-54 ◽  
Author(s):  
P. Thaddeus
Keyword(s):  
Star Formation ◽  
Interstellar Medium ◽  
Molecular Clouds ◽  
Physical State ◽  
Molecular Gas ◽  
Spectroscopic Techniques ◽  
Low Density ◽  
Recombination Line ◽  
Interstellar Gas ◽  
Impossible Task

To attempt to understand star formation without knowing the physical state of the dense interstellar molecular gas from which stars are made is an almost impossible task. Star formation has developed late as a branch of astrophysics largely for lack of observational data, and in particular, has lagged badly behind the study of the atomic and ionized components of the interstellar gas because spectroscopic techniques which work well at low density have an unfortunate tendency to fail when the density is high. Optical spectroscopy, which has been applied to the interstellar medium for over 70 years, has made little progress in regions of high density because of obscuration, and the same is true a fortiori of spacecraft spectroscopy in the UV; radio 21-cm and recombination line observations, although unhampered by obscuration, are unsatisfactory because the dense condensations are almost entirely molecular in composition.

scholarly journals Comparing ice composition in dark molecular clouds

2008 ◽  
Vol 4 (S251) ◽  
pp. 47-48 ◽  
Author(s):  
C. Knez ◽  
M. Moore ◽  
S. Travis ◽  
R. Ferrante ◽  
J. Chiar ◽  
...  
Keyword(s):  
Star Formation ◽  
Interstellar Medium ◽  
Molecular Clouds ◽  
Organic Molecules ◽  
Dark Cloud ◽  
Preliminary Results ◽  
Level Of Activity ◽  
Star Formation Activity

AbstractWe present 5–20 μm Spitzer/IRS spectroscopy toward stars behind dark molecular clouds. We present preliminary results from the Serpens dark cloud to show the variation between environments within a cloud. We are surveying 3 clouds with varying levels of star formation activity. Serpens has the highest level of activity from our 3 clouds. We show that location as well extinction can cause variations in ice composition. We also find that some lines of sight contain organic molecules such as methane and methanol, and the first detection of acetylene ice in the interstellar medium. We believe the high extinction lines of sight have been enriched by star formation activity near those lines of sight.

Formation of structure in star-forming clouds

1990 ◽  
Vol 68 (9) ◽  
pp. 808-823
Author(s):  
Ralph E. Pudritz
Keyword(s):  
Star Formation ◽  
Magnetic Fields ◽  
Interstellar Medium ◽  
Physical Properties ◽  
Molecular Clouds ◽  
Fundamental Theory ◽  
Wave Pressure ◽  
Star Forming ◽  
Effective Wave ◽  
Hydromagnetic Waves

Star formation occurs in massive, dense, molecular clouds in the interstellar medium. These clouds have a rich substructure consisting of dense clumps and extended filaments. Since stars only form within these dense clumps, any fundamental theory of star formation must predict their physical properties. This review focusses on the physics of molecular clouds and discusses in this context a particular mechanism for the formation of structure that is well supported by the observations. Strong hydromagnetic waves are likely to be excited in molecular clouds since it is observed that cloud magnetic fields have energy densities close to gravity. These waves support the cloud against global gravitational collapse by providing an effective wave "pressure". This review also shows that waves may control the formation of structure in molecular clouds.

scholarly journals Galactic star formation in parsec-scale resolution simulations

2010 ◽  
Vol 6 (S270) ◽  
pp. 487-490
Author(s):  
Leila C. Powell ◽  
Frederic Bournaud ◽  
Damien Chapon ◽  
Julien Devriendt ◽  
Adrianne Slyz ◽  
...  
Keyword(s):  
Star Formation ◽  
High Resolution ◽  
Interstellar Medium ◽  
Molecular Clouds ◽  
Giant Molecular Clouds ◽  
Gas Distribution ◽  
Computational Problem ◽  
Cold Gas

AbstractThe interstellar medium (ISM) in galaxies is multiphase and cloudy, with stars forming in the very dense, cold gas found in Giant Molecular Clouds (GMCs). Simulating the evolution of an entire galaxy, however, is a computational problem which covers many orders of magnitude, so many simulations cannot reach densities high enough or temperatures low enough to resolve this multiphase nature. Therefore, the formation of GMCs is not captured and the resulting gas distribution is smooth, contrary to observations. We investigate how star formation (SF) proceeds in simulated galaxies when we obtain parsec-scale resolution and more successfully capture the multiphase ISM. Both major mergers and the accretion of cold gas via filaments are dominant contributors to a galaxy's total stellar budget and we examine SF at high resolution in both of these contexts.

scholarly journals Magnetic fields and star formation – new observational results

2006 ◽  
Vol 2 (S237) ◽  
pp. 141-147
Author(s):  
Richard M. Crutcher ◽  
Thomas H. Troland
Keyword(s):  
Magnetic Field ◽  
Star Formation ◽  
Magnetic Fields ◽  
Interstellar Medium ◽  
Observational Data ◽  
Molecular Clouds ◽  
Dark Cloud ◽  
Magnetic Field Model ◽  
Field Lines ◽  
Cloud Cores

AbstractAlthough the subject of this meeting is triggered star formation in a turbulent interstellar medium, it remains unsettled what role magnetic fields play in the star formation process. This paper briefly reviews star formation model predictions for the ratio of mass to magnetic flux, describes how Zeeman observations can test these predictions, describes new results – an extensive OH Zeeman survey of dark cloud cores with the Arecibo telescope, and discusses the implications. Conclusions are that the new data support and extend the conclusions based on the older observational results – that observational data on magnetic fields in molecular clouds are consistent with the strong magnetic field model of star formation. In addition, the observational data on magnetic field strengths in the interstellar medium strongly suggest that molecular clouds must form primarily by accumulation of matter along field lines. Finally, a future observational project is described that could definitively test the ambipolar diffusion model for the formation of cores and hence of stars.

scholarly journals The Supernova – ISM/Star-formation interplay

2013 ◽  
Vol 9 (S296) ◽  
pp. 265-272
Author(s):  
Gerhard Hensler
Keyword(s):  
Star Formation ◽  
Interstellar Medium ◽  
Molecular Clouds ◽  
Numerical Models ◽  
Evolutionary Models ◽  
Star Forming ◽  
Supernova Explosions ◽  
Representative Selection ◽  
Supernova Feedback ◽  
Selection Of

AbstractSupernovae are the most energetic stellar events and influence the interstellar medium by their gasdynamics and energetics. By this, both also affect the star formation positively and negatively. In this paper, we review the complexity of investigations aiming at understanding the interchange between supernova explosions with the star-forming molecular clouds. Commencing from analytical studies the paper advances to numerical models of supernova feedback from superbubble scales to galaxy structure. We also discuss parametrizations of star-formation and supernova-energy transfer efficiencies. Since evolutionary models from the interstellar medium to galaxies are numerous and are applying multiple recipes of these parameters, only a representative selection of studies can be discussed here.

scholarly journals Physical and Dynamical Conditions in Interstellar Clouds

1980 ◽  
Vol 87 ◽  
pp. 1-19 ◽  
Author(s):  
N.J. Evans
Keyword(s):  
Star Formation ◽  
Interstellar Medium ◽  
Formation Process ◽  
Molecular Clouds ◽  
Interstellar Molecules ◽  
Interstellar Clouds ◽  
New Class ◽  
Galactic Structures ◽  
To Come

The most far-reaching result to come from the study of interstellar molecules has been the recognition of a new class of galactic structures - molecular clouds. These clouds appear to contain most of the mass of the interstellar medium and are the objects from which new stars are formed. Thus, a prerequisite for any understanding of the star formation process is a knowledge of the physical and dynamical conditions in molecular clouds.

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