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Carbon abundances using hydrodynamic model atmospheres

l. Carbon abundances using hydrodynamic model atmospheres. Ana Elia Garc ía Pérez Co: Stelios Tsangarides Sean Ryan Martin Asplund. Background. A significant fraction of metal-poor stars show a high content of carbon Binarity (AGB stars) & Pop III supernovae.

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Carbon abundances using hydrodynamic model atmospheres

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  1. l Carbon abundances using hydrodynamic model atmospheres Ana Elia García Pérez Co: Stelios Tsangarides Sean Ryan Martin Asplund

  2. Background • A significant fraction of metal-poor stars show a high content of carbon • Binarity (AGB stars) & Pop III supernovae Are these high values due to systematic effects?

  3. Abundance determinations stellar atmosphere modelling Surface inhomogeneities 1D  3D spectral synthesis modelling

  4. Abundance determinations • Plane-parallel or spherical model atmospheres (1D) (z), T(z), P(z) or (r), T(r), P(r) • Radiation is determined by the local properties of the matter (LTE) n= f(T, ) • Molecular equilibrium in LTE

  5. Spectral line formation in 3D model atmospheres (Asplund 2003)

  6. Grid of 3D model atmospheres • 5767 4.44 0.00 200x200x82 sun_extend fsun201.sav • 5768 4.44 0.00 100x100x82 sun fsun101.sav • 5768 4.44 0.00 50x50x82 fsun fsun05.sav • 5822 4.44 -1.00 100x100x82 sun-1.0 fsun-1.002.sav • 5837 4.44 -2.00 100x100x82 sun-2.0 fsun-2.00506.sav • 5890 4.44 -3.00 100x100x82 sun-3.0 fsun-3.003.sav • 6191 4.04 0.00 100x100x82 t62g40m00 ft62g40m0000.sav • 6180 4.04 -1.00 100x100x82 t62g40m10 ft62g40m1000.sav • 6178 4.04 -2.00 100x100x82 t62g40m20 ft62g40m2000.sav • 6205 4.04 -3.00 100x100x82 t62g40m30 ft62g40m3000.sav • 6514 3.96 0.00 100x100x82 procyon fprocyon09.sav • 6356 4.04 -2.25 100x100x82 84937 f849370809.sav • 5691 3.67 -2.50 100x100x82 140283 f14028308.sav • 6469 4.04 -3.00 100x100x82 t64g40m30 ft62g40m3000.sav Work in progress 6180 4.04 -1.00 100x100x82 t62g40m10 6178 4.04 -2.00 100x100x82 t62g40m20 6205 4.04 -3.00 100x100x82 t62g40m30

  7. 3D modelling of the formation of a CH line at 4329.2 Å 6180/4.04/-1.00 -0.2 dex ... 3D - 1D +0.2 dex

  8. 3D effects vs metallicity (Asplund 2002)

  9. Conclusions • The formation of the CH line at 4329.2 Å seems to be affected by surface inhomogeneities • Typical 3D effects are ~0.1 dex for a metallicity value of -1.00 • Effects at lower metallicities need to be investigated so… Have to go back and fight with the code!

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