A Very Massive Star

A massive star - forming region in a very early stage of evolution

We present results from a study of two luminous IRAS sources thought to be young massive star-forming regions and which have no previously detected radio continuum emission: IRAS 15596-5301 and IRAS 16272-4837. Our study incorporates sensitive ATCA radio continuum data, SEST 1.2-mm continuum (using the new SIMBA bolometer) and line data, as well as data taken from the MSX database. The results ...

Massive Star Formation

Massive Star and Star Cluster Formation

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 models. I then discuss: the initial conditions of star cluster formation as traced by infrared dark clouds; the cluster formation timescale; and comparison of th...

The massive star IMF

We review our current knowledge on the IMF in nearby environments, massive star forming regions, super star clusters, starbursts and alike objects from studies of integrated light, and discuss the various techniques used to constrain the IMF. In most cases, including UV-optical studies of stellar features and optical-IR analysis of nebular emission, the data is found to be compatible with a “un...

Massive Star Outflows

Molecular outflows in the form of wide-angle winds and/or well-collimated jets are associated with young stellar objects of all luminosities. Independent studies have established that the mass outflow rate is proportional to L bol for Lbol = 0.3 to 10 5 L⊙, suggesting that there is a strong link between accretion and outflow for a wide range of source luminosity and there is reasonable evidence...