8-12 July 2013
Africa/Johannesburg timezone
<a href="http://events.saip.org.za/internalPage.py?pageId=13&confId=32"><font color=#ff0000>SAIP2013 PROCEEDINGS AVAILABLE</font></a>

Astereoseismology of Beta Cepheid Stars using multicolor photometry: Mode Identication.

10 Jul 2013, 17:40
1h
Poster Presentation Track D1 - Astrophysics Poster2

Speaker

Mr LLOYD KEELEY (NORTH WEST UNIVERSITY)

Would you like to <br> submit a short paper <br> for the Conference <br> Proceedings (Yes / No)?

Yes

Level for award<br>&nbsp;(Hons, MSc, <br> &nbsp; PhD)?

MSc

Abstract content <br> &nbsp; (Max 300 words)

The thesis involves the study of young population B type Cepheid
variable stars using seismic waves to study their oscillation modes. The
goal is to identify the modes associated with the frequencies over the
ranges of the quantum numbers n and l so that deductions can be made
about the internal structure and composition of the star. For the
Cepheids there are two types of pulsation modes p, or pressure modes,
and g, or gravity modes, each of which penetrate to dierent depths in
the star thus probe conditions in the outer and inner parts of the star.
Time series data collected from observations at Sutherland will be Fourier
analyzed and modes identied from the frequency peaks in the spectrum.
In the theoretical model, the amplitude ratios are calculated for dier-
ent values of the degree l of the spherical harmonic and wavelength
and the computed values then compared with amplitude ratios obtained
from observational measurements at the same wavelengths. The theoret-
ical model includes information about metallicity, temperature, density,
pressure and the known atmospheric parameters with regards to the hy-
pothetical Cepheid star. Once the theoretical amplitudes are matched
with the observational amplitudes, within a certain error bar, then the
mode l can be identied. My goals will be to analyze the observed pulsa-
tions in certain Cepheid stars to obtain information about their physical
parameters such as size and evolutionary state.

Main supervisor (name and email)<br>and his / her institution

Professor Medupe

Apply to be<br> considered for a student <br> &nbsp; award (Yes / No)?

Yes

Primary author

Mr LLOYD KEELEY (NORTH WEST UNIVERSITY)

Presentation Materials

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