Public Dirac Lecture 2008

A PhD scholarship in astronomy is available to work with Professor Michael Burton investing the earliest stages of massive star formation.  The applicant should have an honours degree in Physics, Chemistry, Mathematics, Engineering or Computing Science.

The Department of Astrophysics is one of Australia's leading university research groups in astronomy.  We have a particularly strong program in millimetre-wave astronomy, making use of the world-leading facilities Australia has for these kinds of observations, which enable us to study the emission from molecules in space.  In particular, we make use of the 22m Mopra telescope, located at Coonabarabran in NSW, together with the NANTEN2 telescope on the 5,000m elvation altiplano of Chile.  These facilities provide formidable spectrometers which allows one to study the astrochemistry associated with the formation of stars.

Funded in by part of an ARC Discovery grant, this scholarship will provide $15K per year.  PhD students in the School may simultaneously accept Postgraduate Assistantships, which provide additional guaranteed income of up to $10k per year, in return for agreed teaching duties. The scholarships do not cover tuition fees. Australian and New Zealand students do not pay tuition fees.  The university campus is located in the East of Sydney, close to Coogee Beach.

For further information, please contact Professor Michael Burton, School of Physics, University of New South Wales, Sydney, NSW 2052.  Tel 02-9385-4553, Email m.burton@unsw.edu.au. URL:http://www.phys.unsw.edu.au/STAFF/ACADEMIC/burton.html

A description of the project is given below:

Research Project: The Earliest stages of Massive Star Formation

The evolution of our Galaxy is driven by the massive stars that reside within it.  These are stars greater than ten times the mass of the Sun, and thousands of times brighter.  Their prodigious luminosities drive energy flows, which in turn power the cycle of elements between the stars and the gas, and back to the stars again. Each time the cycle is passed through it is enriched by the products of nucleosynthesis, occurring in the cores of the stars.  The crucible of this process is the formation of these massive stars.  Yet this remains somewhat of an enigma, for a number of reasons.  Massive star formation takes place rapidly.  The nearest examples are distant from us. It takes place in clusters with stars at different stages of formation.  Many different physical processes are taking place simultaneously.  This makes it a fascinating challenge to study!

In recent years the advent of sensitive and high angular resolution infrared cameras has made it possible to detect the forming stars.  Combined with new millimetre-wave telescopes and interferometers that allow us to observe the rich range of molecules present, we are now able to determine the physical state of the molecular cores where massive stars are born, and to follow their childhood as the star passes through a series of stages being emerging on the Main Sequence.

In particular a time-dependent chemistry is evident, complex organic molecules created inside "hot molecular cores" surrounding an incipient star.  The molecules present at any time provide a signpost which points to the stage star formation has reached - if only we could read the signpost.  One aspect of this project is to decode the language the signpost is written - by determining what molecules are present in a variety of cores, and how these change as the cores develop towards the formation of a new star.  This involves observation using new millimetre-wave telescopes, both in Australia and under construction on the Atacama plateau of northern Chile.

How many stars form in a hot molecular core?  Do they follow a universal initial mass function, and does this vary from core to core? What physical characteristics of the core determine the range of stars that form?  Such questions can be tackled through deep infrared observations.

These will allow us to uncover the newly forming stars while they remain deeply embedded in their natal cores, and to investigate their spectral characteristics to indicate what type of star(s) will emerge from it.

This PhD project will thus involve millimetre-wave and infrared observations of molecular clouds where massive star formation is underway, and the subsequent analysis and interpretation of this data.  It will make use of the single-dish Mopra Telescope and the interferometer of the Australia Telescope to find where the molecular species are.  It will use the new NANTEN2 telescope on the 5,000m Atacama plateau of Chile to determine the excitation of the clouds.  It will also use infrared telescopes in Chile, combined with data from space infrared telescopes, to measure the stellar content and determine what kind of stars are forming.