Download School of Physics Multiwavelength Observations of Evolved Stars Research project in Astrophysics

School of Physics
Research project in
Astrophysics
Multiwavelength Observations of Evolved Stars
Research supervisor:
Prof. Brian Espey, Astrophysics Group
Scientific Background / Current Research
The project involves observation and theoretical modelling of stellar
systems containing evolved giant stars with masses similar to that
of our own Sun. Although supernovae are showy objects, stars with
mass similar to our Sun are much more plentiful and when they
evolve to the red giant stage they begin to lose processed material
in the form of a cool wind. These stars contribute a significant
quantity of the carbon, nitrogen and oxygen in the interstellar
medium, as well as modifying the star’s future evolution.
The exact mechanism of mass-loss occurs in non-dusty
giants is still unknown. To determine the physical
conditions in the outer layers of the star where the wind
begins we use binary star systems where a hot companion
star is periodically eclipsed by its giant companion.
Comparison of eclipsed with uneclipsed spectra enables us
to isolate the spectrum of different layers in the giant’s
atmosphere and diagnose conditions layer-by-layer with the
same relative spatial resolution as the thickness of an onion
skin relative to the onion(!) – resolution unobtainable by any
other means.
Project
By using a combination of high resolution ground-based and
Top of figure: Uneclipsed data
(black,
top)
and
eclipsed
data
space-borne (including Hubble Space Telescope) spectra, the
with model overlaid (in red).
physical parameters of the outer atmosphere of a sample of giant Spectra below show FeII
template,
and
other
lines.
stars will be determined. With these data a complete model will be
developed using a state-of-the-art stellar atmosphere code on
TCD high performance computing facilities.
Funding
Applicants should discuss funding with the Research Supervisor. They should apply
for funding from the following sources: Irish Research Council (deadline 11 February,
2015), TCD PG Scholarship and School of Physics Studentship schemes.
More information / References
Previous PhD work: see: http://www.tcd.ie/Physics/Astrophysics/theses.php
Contact details
[email protected]
Room no: SNIAM 3.17
tel. +353 1 896 2680
© 22 January 2015, School of Physics, TCD