Related papers: Massive Star Formation
Star formation is intimately linked to the dynamical evolution of molecular clouds. Turbulent fragmentation determines where and when protostellar cores form, and how they contract and grow in mass via accretion from the surrounding cloud…
Massive stars influence the surrounding universe far out of proportion to their numbers through ionizing radiation, supernova explosions, and heavy element production. Their formation requires the collapse of massive interstellar gas clouds…
We model the formation of high-mass stars, specifying the accretion rate in terms of the instantaneous and final mass of the star, the ambient pressure of the star-forming region and the form of polytropic pressure support of the…
Massive stars (> 8 $M_\odot$) are known to have high degrees of multiplicity, e.g., with about 60% in triples or higher-order multiples. Such high levels of multiplicity may arise during formation (primary multiplicity) or through dynamical…
Although the basic physics of star formation is classical, numerical simulations have yielded essential insights into how stars form. They show that star formation is a highly nonuniform runaway process characterized by the emergence of…
Using our recently improved understanding of star cluster physics, we are now within reach of answering a number of fundamental questions in contemporary astrophysics. Star cluster physics has immediate bearing on questions ranging from the…
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…
This chapter reviews progress in the field of massive star formation. It focuses on evidence for accretion and current models that invoke high accretion rates. In particular it is noted that high accretion rates will cause the massive young…
Young stars form on a wide range of scales, producing aggregates and clusters with various degrees of gravitational self-binding. The loose aggregates have a hierarchical structure in both space and time that resembles interstellar…
The conditions that lead to self-regulated star formation, star bursts and the formation of massive stellar clusters are discussed. Massive stars have a strong impact on their environment, especially on the evolution of dwarf galaxies which…
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…
Here we model a star forming factory in which the continuous creation of stars results in a highly concentrated, massive (globular cluster-like) stellar system. We show that under very general conditions a large-scale gravitational…
Star formation in strongly self-gravitating cloud cores should be similar at all redshifts, forming single or multiple stars with a range of masses determined by local magneto-hydrodynamics and gravity. The formation processes for these…
Star formation has often been studied by separating the low- and high-mass regimes with an approximate boundary at 8M_sun. While some of the outcomes of the star-formation process are different between the two regimes, it is less clear…
Massive stars likely form by accretion and the evolutionary track of an accreting forming star corresponds to what is called the birthline in the HR diagram. The shape of this birthline is quite sensitive to the evolution of the entropy in…
The accretion phase of star formation is investigated in magnetically-dominated clouds that have an initial subcritical mass-to-flux ratio. We employ nonideal magnetohydrodynamic simulations that include ambipolar diffusion and ohmic…
Recent simulations and observations suggest that star clusters form via the assembling of smaller sub-clusters. Because of their short relaxation time, sub-clusters experience core collapse much earlier than virialized solo-clusters, which…
Massive OB stars play an important role in the evolution of molecular clouds and star forming regions. The OB stars both photo--ionize molecular gas as well as sweep up and compress interstellar gas through winds, ionization fronts, and…
Observations of pre-/proto-stellar cores in young star-forming regions show them to be mass segregated, i.e. the most massive cores are centrally concentrated, whereas pre-main sequence stars in the same star-forming regions (and older…
Stars and star clusters form by gravoturbulent fragmentation of interstellar gas clouds. The supersonic turbulence ubiquitously observed in Galactic molecular gas generates strong density fluctuations with gravity taking over in the densest…