Related papers: Remarks on Rapid vs. Slow Star Formation
Stars in star clusters are thought to form in a single burst from a common progenitor cloud of molecular gas. However, massive, old globular clusters -- with ages greater than 10 billion years and masses of several hundred thousand solar…
We consider the problem of the apparent lack of old T Tauri stars in low-mass star forming regions in the framework of the standard model of low-mass star formation. We argue that the similarity between molecular cloud lifetime and…
We review current understanding of star formation, outlining an overall theoretical framework and the observations that motivate it. A conception of star formation has emerged in which turbulence plays a dual role, both creating…
We review the progress that has been made in observing and analyzing molecular cloud structure in recent years. Structures are self-similar over a wide range of scales with similar power law indices independent of the star forming nature of…
Understanding how stars form, evolve and impact molecular clouds is key to understanding why star formation is such an inefficient process globally. In this paper, we use the infrared bright fraction, $f_\text{IRB}$ (the fraction of a given…
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…
Dust grains influence many aspects of star formation, including planet formation, opacities for radiative transfer, chemistry, and the magnetic field via Ohmic, Hall, and ambipolar diffusion. The size distribution of the dust grains is the…
The thermal and chemical evolution of gravitationally collapsing protostellar clouds is investigated, focusing attention on their dependence on metallicity. Calculations are carried out for a range of metallicities spanning the local…
In this chapter, we will cover how stars form from the stellar nurseries that are giant molecular clouds. We will first review the physical processes that compete to regulate star formation. We then review star formation in turbulent,…
A long-standing problem in low-mass star formation is the "luminosity problem," whereby protostars are underluminous compared to the accretion luminosity expected both from theoretical collapse calculations and arguments based on the…
We present a simple model of binary star formation based on the assumption that rotating prestellar cores collapse to form rings and these rings then fragment into protostars. We assume that each ring spawns a small number (N <= 6) of…
We explore the constraints on globular cluster formation provided by the observed conditions in starbursts where globulars are currently forming, and by the observed properties of young and old globular clusters. We note that the pressure…
Newly formed stars are often observed to possess circumstellar disks, from which mass continues to be accreted onto the star and fed into outflowing jets, and which eventually may evolve into dusty debris disks and planetary systems. Recent…
Our knowledge of the initial conditions and early stages of high mass star formation is very limited. We will review recent surveys of regions in the early stages of massive star formation using molecular tracers of high density and dust…
The enormous radiative and mechanical luminosities of massive stars impact a vast range of scales and processes, from the reionization of the universe, to the evolution of galaxies, to the regulation of the interstellar medium, to the…
I review the status of massive star formation theories: accretion from collapsing, massive, turbulent cores; competitive accretion; and stellar collisions. I conclude the observational and theoretical evidence favors the first of these…
We argue that rich star clusters take at least several local dynamical times to form, and so are quasi-equilibrium structures during their assembly. Observations supporting this conclusion include morphologies of star-forming clumps,…
Star clusters are observed to form in a highly compact state and with low star-formation efficiencies, and only 10 per cent of all clusters appear to survive to middle- and old-dynamical age. If the residual gas is expelled on a dynamical…
Hertzsprung-Russell diagrams of star forming regions show a large luminosity spread. This is incompatible with well-defined isochrones based on classic non-accreting protostellar evo- lution models. Protostars do not evolve in isolation of…
Starting from a prestellar core with a size of $1.2\times10^4$ AU, we calculate the evolution of a gravitationally collapsing core until $\sim2000$ yr after protostar formation using a three-dimensional resistive magnetohydrodynamic…