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Exploring Astero-seismology in South Africa Through Seismic Waves and Pulsating Stars

Dive into the world of astero-seismology in South Africa by monitoring time variations in intrinsic variables to reveal properties like mass, luminosity, and rotation rate. Explore seismic waves trapped in stars and how stars pulsate according to specific modes, offering insights into their composition and structure. Discover observational studies, modes identification methods, and the search for new pulsating stars like rapid oscillating Ap stars and pulsating sdB stars. Unveil the observational facilities and theoretical frameworks used in this cutting-edge research.

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Exploring Astero-seismology in South Africa Through Seismic Waves and Pulsating Stars

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  1. Time Domain Astrophysics in South Africa 2 Astero-seismology

  2. Astero-seismology • Monitoring Time variations in intrinsic variables in order to infer their properties such as mass, luminosity, rotation rate, internal composition

  3. Seismic Waves trapped in Stars • Stars pulsate according to y=An( r ) Ylm (theta, phi) exp(-omega t) Where n l m describe a mode A good start to astero-seismology is in determining these for as many modes as possible

  4. Probing a star with seismic waves

  5. Asteroseismology Research in South Africa • Observational Studies include - mode identification using photometry alone (determines l) - mode identification using Baade-Wesselink methods (combination) - mode-identification by observing line profile variations On roAp stars, delta Scuti, sdB stars, beta Cepheid etc

  6. Search for new Pulsating stars • Rapidly Oscillating Ap stars (SAAO) 5 min < Ppuls<16 min

  7. like nothing you have ever seen dipole(-like) new, improved mode strange doublet Frequency Spectrum

  8. Pulsating sdB stars • hot Horizontal Branch stars with temperatures of about 30,000 K • Periods 2 -3 minutes

  9. Observational Facilities • Photo-electric photometers • CCDs (also have frame-transfer) • Giraffe spectrograph {R = 39000, wavelength 3820 - 9240 angstrom, V < 9} • SALT ?

  10. Theory • Non-linear theory (SAAO) • Radiative Transfer and Oscillations in A stars (UCT/SAAO)

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