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 …

▪ Abstract This review discusses three main topics: evolution to the ultra-compact (UC) state;
the properties of UC HII regions and their environments; and UC HII regions as probes of …

A thermal light-emitting source, such as a black body or the incandescent filament of a light
bulb, is often presented as a typical example of an incoherent source and is in marked …

Observations indicate that massive stars in the Galaxy form in regions of very high surface
density, Σ∼ 1 g cm-2. Clusters containing massive stars and globular clusters have a …

We present a grid of radiation transfer models of axisymmetric young stellar objects (YSOs),
covering a wide range of stellar masses (from 0.1 to 50 M☉) and evolutionary stages (from …

We present a detailed 1.2 mm continuum and CS spectral line study of a large sample of 69
massive star forming regions in very early stages of evolution, most of them prior to building …

Formation of massive stars by accretion requires a high accretion rate of $\dot {M} _\ast>
10^{-4} M_ {\odot}\,{\rm yr^{-1}} $ to overcome the radiation pressure barrier of the forming …

We investigate the physical processes that lead to the formation of massive stars. Using a
numerical simulation of the formation of a stellar cluster from a turbulent molecular cloud, we …

Massive stars (with mass m*> 8 solar masses M⊙) are fundamental to the evolution of
galaxies, because they produce heavy elements, inject energy into the interstellar medium …

We describe a systematic program aimed at identifying and characterizing candidate high-
mass protostellar objects (HMPOs). Our candidate sample consists of 69 objects selected by …