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Model atmospheres and specra of hydef giants and peculiar stars

Yakiv V.Pavlenko Main astronomical observatory 27 Sabolotnoho, Kyiv, Ukraine www.mao.kiev.ua/staff/yp. Model atmospheres and specra of hydef giants and peculiar stars. Collaborators. J.Tennyson (UCL) Greg Harries (UCL) Yakovina Larisa(MAO) Kaminsky Bogdan (MAO) Hugh Jones (UH)

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Model atmospheres and specra of hydef giants and peculiar stars

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  1. Yakiv V.Pavlenko Main astronomical observatory 27 Sabolotnoho, Kyiv, Ukraine www.mao.kiev.ua/staff/yp Model atmospheres and specra of hydef giants and peculiar stars

  2. Collaborators J.Tennyson (UCL) Greg Harries (UCL) Yakovina Larisa(MAO) Kaminsky Bogdan (MAO) Hugh Jones (UH) Bob Barver (UCL) Nye Evans(Keele) Hilmar Duerbeck(OU) Sveta Zhukovska (MAO) Thomas Geballe (Gemini)

  3. Stars of interest: Hydrogen-rich stars --- M-giants --- C-giants --- V838 Mon --- RS Oph Hydrogen poor stars ---R CrB et al. ---Sakurai’s object

  4. Outline Model atmospheres and fits to SEDs Isotopic ratios (12C/13C) Abundances

  5. PROCEDURE Model atmospheres SAM12 (ATLAS12) 1D, Convection + radiation, LTE, No sinks and sources of energy Opacity sampling for line opacity Synthetic spectra WITA 1D, LTE, Voigt function for lines VCS theory for H lines SEDs

  6. OPACITIES: C/O < 1, Opacity sources: VO, TiO; H2O, CO Methane C/O > 1 CN, CO, CH, C2,HCN, C3, --- [H]?? --- isotopes!

  7. Problems: • Opacities (missed continuum absorption in the blue, line lists (both atomic and molecular), isotops, • chemical abundances and equilibrium, • 3-D convection, • sphericity effects, • the dust, • stellar winds.

  8. “...Given the web of interconnected uncertainties and errors presented here, one is initially tempted to give up on stellar atmospheres completely and turn to something simple like cosmology.” V.Trimble & R.A. Bell:

  9. Astronomy often progresses amoeba- like: the advance in one pseudopod may not move the animal very far, but permits other parts to advance in their turn and can reveal portions of the organism that are in danger of being left behind. V.Trimble, R.A.Bell, Q.Jl.R.astr.Soc.(1981),22, 361-379

  10. M-giantsvsC-giants

  11. H-def stars

  12. Asplund et al. (2000)

  13. Family of R CrB stars

  14. Opacities...

  15. Pavlenko (2003)

  16. Pavlenko (2003)

  17. Topbase vs kurucz & Hofsaess (Pavlenko & Zhukovska 2003)

  18. http://www.mao.kiev.ua/ staff/yp/Results/CNO_bf.tar.gz

  19. Pavlenko (2003)

  20. Model atmospheres & spectra vs opacities & H/He

  21. Sakurai's object (V4334 Sgr)

  22. CO in Arcturus

  23. CO in Sakurai's object

  24. / to be continued...

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