Related papers: Turbulence decay and cloud core relaxation in mole…
Molecular clouds are the principle stellar nurseries of our universe, keeping them in the focus of both observational and theoretical studies. From observations, some of the key properties of molecular clouds are well known but many…
We compile a holistic scenario for molecular cloud (MC) evolution and control of the star formation efficiency (SFE), and present a first set of numerical tests of it. A {\it lossy} compressible cascade can generate density fluctuations and…
We describe an overall picture of galactic-scale star formation. Recent high-resolution magneto-hydrodynamical simulations of two-fluid dynamics with cooling/heating and thermal conduction have shown that the formation of molecular clouds…
Giant molecular clouds contain supersonic turbulence and simulations of magnetohydrodynamic turbulence show that these supersonic motions decay in roughly a crossing time, which is less than the estimated lifetimes of molecular clouds. Such…
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…
The gas clouds of the interstellar medium have a fractal structure, the origin of which has generally been thought to lie in turbulence. The energy of turbulence could come from galactic rotation at large-scale, then cascade down to be…
We present numerical studies of compressible, decaying turbulence, with and without magnetic fields, with initial rms Alfven and Mach numbers ranging up to five, and apply the results to the question of the support of star-forming…
In order to investigate the origin of the interstellar turbulence, detailed observations in the CO J=1--0 and 3--2 lines have been carried out in an interacting region of a molecular cloud with an HII region. As a result, several 1,000 to…
We consider the conditions required for a cluster core to shrink, by adiabatic accretion of gas from the surrounding cluster, to densities such that stellar collisions are a likely outcome. We show that the maximum densities attained, and…
The angular momentum of a molecular cloud core plays a key role in star formation, since it is directly related to the outflow and the jet emanating from the new-born star and it eventually results in the formation of the protoplanetary…
A roughly constant temperature over a wide range of densities is maintained in molecular clouds through radiative heating and cooling. An isothermal equation of state is therefore frequently employed in molecular cloud simulations. However,…
Aerosol-cloud interactions represent the largest uncertainty in climate-change assessment, and while cloud turbulence is considered crucial for droplet growth, its precise role remains unclear. Our laboratory-controlled studies show that…
The physical conditions in molecular clouds control the nature and rate of star formation, with consequences for planet formation and galaxy evolution. The focus of this review is on the conditions that characterize regions of star…
We present a direct numerical and analytical study of driven supersonic MHD turbulence that is believed to govern the dynamics of star-forming molecular clouds. We describe statistical properties of the turbulence by measuring the velocity…
This review summarizes the argument for molecular clouds being dominated by turbulence, most likely super-Alfvenic turbulence. Five lines of observational evidence are given: molecular linewidths and line shapes, nonequilibrium chemical…
Star formation in galaxies is inefficient, and understanding how star formation is regulated in galaxies is one of the most fundamental challenges of contemporary astrophysics. Radiative cooling, feedback from supernovae and active galactic…
I discuss the role of self-gravity and radiative heating and cooling in shaping the nature of the turbulence in the interstellar medium (ISM) of our galaxy. The heating and cooling cause it to be highly compressible, and, in some regimes of…
Context. Stellar feedback regulates star formation and shapes the interstellar medium, yet its role during the collapse of molecular clouds remains uncertain over a wide range of initial conditions. Aims. We explore how stellar winds and…
The mass flux of solar and stellar winds is a key quantity for stellar evolution and space weather, yet its physical regulation mechanism remains an unsolved problem. In particular, conventional Alfv\'en wave--driven models that…
The role of turbulent fragmentation in regulating the efficiency of star formation in interstellar clouds is examined from new wide field imaging of 12CO and 13CO J=1-0 emission from the Rosette and G216-2.5 molecular clouds. The Rosette…