Related papers: Massive Star Formation: The Power of Interferometr…
In the present-day universe, it appears that most, and perhaps all, massive stars are born in star clusters. It also appears that all star clusters contain stars drawn from an approximately universal initial mass function, so that almost…
We consider some aspects of the evolution of massive stars which can only be elucidated by means of "indirect" observations, i.e. measurements of the effects of massive stars on their environments. We discuss in detail the early evolution…
How massive were the first stars? This question is of fundamental importance for galaxy formation and cosmic reionization. Here we consider how protostellar feedback can limit the mass of a forming star. For this we must understand the rate…
We perform calculations of pre-main sequence evolution of stars from 1 to $85 M_{\odot}$ with growing accretion rates $\dot{M}$. The values of $\dot{M}$ are taken equal to a constant fraction $\tilde{f}$ of the rates of the mass outflows…
In order to distinguish between the various components of massive star forming regions (i.e. infalling, outflowing and rotating gas structures) within our own Galaxy, we require high angular resolution observations which are sensitive to…
Star formation is a multi-scale, multi-physics problem ranging from the size scale of molecular clouds ($\sim$10s pc) down to the size scales of dense prestellar cores ($\sim$0.1 pc) that are the birth sites of stars. Several physical…
Our current understanding of the physical processes of star formation is reviewed, with emphasis on processes occurring in molecular clouds like those observed nearby. The dense cores of these clouds are predicted to undergo gravitational…
The collapse of massive molecular clumps can produce high mass stars, but the evolution is not simply a scaled-up version of low mass star formation. Outflows and radiative effects strongly hinder the formation of massive stars via…
In this review, I present the case for how massive stars may form through stellar collisions. This mechanism requires very high stellar densities, up to 4 orders of magnitude higher than are observed in the cores of dense young clusters. In…
We show that massive stars and stellar clusters are formed simultaneously, the global evolution of the forming cluster is what allows the central stars to become massive. We predict that massive star forming clumps, such as those observed…
New constraints on stellar models are provided by large surveys of massive stars, interferometric observations and asteroseismology. After a review of the main results so far obtained, we present new results from rotating models and discuss…
Astrochemistry is a discipline that studies physico-chemical processes in astrophysical environments. Such environments are characterized by conditions that are substantially different from those existing in usual chemical laboratories.…
Stars form from the gravitational collapse of dense molecular cloud cores. In the protostellar phase, mass accretes from the core onto a protostar, likely through an accretion disk, and it is during this phase that the initial masses of…
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…
This paper reviews the chemistry of star-forming regions, with an emphasis on the formation of high-mass stars. We first outline the basic molecular processes in dense clouds, their implementation in chemical models, and techniques to…
The onset of massive star formation is not well understood because of observational and theoretical difficulties. To find the dense and cold clumps where massive star formation can take place, we compiled a sample of high infrared…
We present a model for the formation of massive ($M > 10 M_\odot$) stars through accretion-induced collisions in the cores of embedded dense stellar clusters. This model circumvents the problem of accreting onto a star whose luminosity is…
This paper discusses how cosmic gas accretion controls star formation, and summarizes the physical properties expected for the cosmic gas accreted by galaxies. The paper also collects observational evidence for gas accretion sustaining star…
In this contribution we review our recent numerical work discussing the essential role of the local cluster environment in assembling massive stars. First we show that massive stars are formed from low mass pre-stellar cores and become…
We present a theoretical model for primordial star formation. First we describe the structure of the initial gas cores as virialized, quasi-hydrostatic objects in accord with recent high resolution numerical studies. The accretion rate can…