PhD position: The formation and early evolution of the most massive stars
The Netherlands Research School for Astronomy (NOVA), as part of its research program Formation and evolution of stars and planetary systems, plans to start a PhD project at the University of Amsterdam focused on the formation and early evolution of the most massive stars.
The mechanism by which the massive stars (M > 8 Msun) form is poorly understood. Even though they are the most luminous objects in the Galaxy, their formation process and early evolution are obscured from view due to the tens to hundreds of magnitudes of (visual) extinction. The recent development of sensitive spectroscopic techniques at near-infrared wavelengths allows for the first time direct detections and quantitative analysis of the characteristics of massive proto-stars. These objects are surrounded by a disk and, in case the photospheric spectrum can be detected, turn out to be “bloated” stars, i.e. are apparently still contracting towards the main sequence. These so-called massive Young Stellar Objects (YSOs) must represent a later phase of formation than the luminous extended disk sources that can be detected at (sub-)millimeter wavelengths, though it is unclear at the moment how these two phases are precisely related. In this project we will study the physical link between these two, likely subsequent phases of massive star formation by combining ALMA and near-IR imaging and spectroscopy of star-forming regions in the Milky Way and Local Group galaxies, in particular the Magellanic Clouds.
Such a multi-wavelength approach will allow us to study massive star formation in an environmental context, including aspects of metallicity and cluster mass/density. By establishing the physical properties of the newly formed stars – such as photospheric parameters, binary properties, rotational characteristics, ionizing fluxes, and radiation-driven winds – we will assess the importance of feedback from this new population on the star formation process in general. State-of-the art spectroscopic analysis methods essential for these studies are currently being developed in the group of prof. De Koter at the UvA.
Our strategy will be to extend the covered wavelength range of the many candidate young massive stars, thereby directly probing the stellar photosphere and wind. Optical/nIR spectra have been (and will be) obtained with X-shooter on the ESO Very Large Telescope in Chile. One of the goals of the project is to relate the found results to observations obtained at longer wavelengths (e.g. ALMA). Reduction, analysis, and interpretation of the obtained data, including the collection of new data, will form a major part of the project that should lead to a PhD at the University of Amsterdam. The position is offered for a period of 4 years and should be taken up in the Fall of 2013. The salary will be on the standard Dutch university scale.
Interested candidates should have a Master degree in astronomy or physics (or the equivalent). Applications should contain a curriculum vitae, a statement of research experience and motivation, and the names of two references, to be sent to:
Prof.dr. L. Kaper, Sterrenkundig Instituut Anton Pannekoek, Universiteit van Amsterdam, Postbus 94249, 1090 GE Amsterdam.
Review of the applications will start on July 1, 2013, and continue until the position is filled.
Deadline: 1 July 2013
Contact: Lex Kaper (L.Kaper@uva.nl) (020-5257474)