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Indirect imaging of stellar non-radial pulsations

Indirect imaging of stellar non-radial pulsations. Svetlana V. Berdyugina University of Oulu, Finland Institute of Astronomy, ETH Zurich, Switzerland. 4. Mode identification. Sectoral modes: Symmetric tesseral modes: Antisymmetric tesseral modes: Zonal modes: Inversion of real data.

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Indirect imaging of stellar non-radial pulsations

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  1. Indirect imaging of stellar non-radial pulsations Svetlana V. Berdyugina University of Oulu, Finland Institute of Astronomy, ETH Zurich, Switzerland

  2. 4. Mode identification • Sectoral modes: • Symmetric tesseral modes: • Antisymmetric tesseral modes: • Zonal modes: • Inversion of real data zonal symmetric antisymmetric sectoral Moletai, August 2005

  3. Sectoral modes: Temperature mapping • T/T=10% Moletai, August 2005

  4. Sectoral modes: Temperature mapping V=3 km /s V=10 km /s Moletai, August 2005

  5. Sectoral modes: Velocity mapping • V =10 km /s Moletai, August 2005

  6. Sym. tesseral modes: Temperature mapping • T/T=10% i =55 i =70 i =85 Moletai, August 2005

  7. Sym. tesseral modes: Velocity mapping • V=9 km/s i =60 i =85 Moletai, August 2005

  8. Antisym. tesseral mode: Temperature mapping • T=10% i =55 i =85 Moletai, August 2005

  9. Antisym. tesseral modes: Velocity mapping • V=9 km/s i =60 i =85 Moletai, August 2005

  10. Zonal modes: Velocity mapping • V=9 km/s i =60 i =85 Moletai, August 2005

  11. Conclusions (I) • Sectoral modes are perfectly recovered • Symmetrical tesseral modes with can be successfully recovered • Antisymmetric tesseral modes with are difficult to recover • Zonal modes are failed to be recovered • Temperature and velocity mapping are equally good for mode identification Moletai, August 2005

  12. ω1 Sco, B1 V,  Cep-type star T=25,000 K log g=4.0 Telting & Schrijvers (1998) Si III triplet at 4565 Å Temperature mapping no assumptions Occamian approach Berdyugina et al. (2003) Inversions of real data: ω1 Sco Moletai, August 2005

  13. ω1 Sco: parameter estimates • Fourier analysis • 15 cycles/day • 13.8 cycles/day Moletai, August 2005

  14. ω1 Sco: parameter estimates period Vsini inclination Moletai, August 2005

  15. ω1 Sco: final solution Moletai, August 2005

  16. ω1 Sco: mode interference Moletai, August 2005

  17. Conclusions (II): • Line-profile variations on ω1 Sco are caused by non-radial pulsations shaped as spherical harmonics • In ω1 Sco sectoral modes with and are possible • Interference of the two modes produces amplitude modulation Moletai, August 2005

  18. HR 3831 roAp-type star T=7650K Nd III at 6145 Å 1860 spectra Velocity mapping Assumption on spherical harmonics Tikhonov regularization Kochukhov (2004) Inversions of real data: HR 3831 Moletai, August 2005

  19. Inversions of real data: HR 3831 Moletai, August 2005

  20. HR 3831: Magnetic field and Nd abundance Moletai, August 2005

  21. Key issues • Both temperature and velocity mapping are equally successful in mode identification • Only rapidly rotating stars can be studied • Simultaneous mapping of different parameters requires additional constraints (measurements or assumptions) Moletai, August 2005

  22. Final conclusion Stellar surface imaging is a useful technique for studying stellar non-radial pulsations Moletai, August 2005

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