PhD project.
Candidates are sought for the following position at Parkes, NSW. Those interested should contact Peter te Lintel Hekkert (plintel@atnf.csiro.au) or Jessica Chapman (jchapman@atnf.csiro.au)
The kinematics of stellar envelopes and the evolution of mass loss between Asymptotic Giant Branch and Planetary Nebulae - White Dwarf stage
During the AGB and Post-AGB stage, the very last stages of stellar evolution, the evolutionary timescale is dominated by the stars' massloss: the star bleeds to death in the relatively short period of a few thousand years.
The material thus returned to the interstellar medium is highly enriched with molecules, like, CO, OH and water, further it includes metals and carbon bearing molecules, like alcohol. This material is the kind of stuff new stars (and planets) are started from.
The mass loss processes of these stars is very poorly understood, mainly because of the small number of sources known in the very last stellar evolutionary stage. Further, there is a lack of observations of the material close to the star: observations in the near infra red and (sub) millimeter regime. In this part of the envelope a large number of melocules are formed (SiO, HCN, MgCO ...) which can now be detected, and for the nearest stars, be mapped.
Recently we have made a small list of nearby Post-AGB stars and have shown that (sub) millimeter observations are the key to understanding the kinematics of the stellar wind. Furthermore, observations of different isotopes of atoms in the stellar wind will produce direct constrains on the stellar evolution models and pulsation modes.
The project consists of three parts: :
obtaining observations with various instruments and techniques, while sampling different parts of the stellar wind and envelope and stellar surface:
radio observations with ATNF's compact array and NRAO's VLA,
near Infrared Observations with SSO/AAT instruments
monitoring of fast evolving parts of the envelope with observations of molecules at millimeter and submillimeter frequencies with Mopra and ESO's SEST.
optical spectroscopic (monitoring) measurements to establish binarity of the system and nova type events on the surface of the star.
- interpretation (and modelling) of the results in terms of stellar evolution, kinematics of the stellar wind and development of the stellar envelope.
integrate the results of 2. with theoretical models of stellar evolution.
It is anticipated that the candidate will spend most of their time on parts 2 and 3.
Some of the observations required for this project have been conducted and the feasability of this project has been shown. The candidate will have a "flying" start, essential for a program of this size and scope, keeping in mind that the program should be finished in three years time.
Requirements for the student:
- Willingness to spend at least half of their time in Parkes, NSW.
Computer literacy: good working knowledge of either c++ or Fortran.
Willingness to spend a few weeks per term at different telescope sites in Australia and the world.
Above average in academic record.
Created: 25/11/95 by Peter te Lintel Hekkert, plintel@atnf.csiro.au Updated: 25/11/95 by Peter te Lintel Hekkert, plintel@atnf.csiro.au