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SAC Seminar - Remo Collet: Characterization of stars with 3D model stellar atmospheres

Oplysninger om arrangementet

Tidspunkt

mandag 1. april 2019,  kl. 10:15 - 11:00

Sted

1525-626

Dear all,  

On Monday 1 April, Remo Collet will give a seminar.

Title: Characterization of stars with 3D model stellar atmospheres


Abstract: Theoretical model stellar atmospheres represent an indispensable tool for quantitatively interpreting astronomical observations and determining the compositions and fundamental parameters of stars and their planets. In this talk, I will present results from realistic, time-dependent, hydrodynamic 3D simulations of stellar atmospheres of solar- and late-type stars, covering a wide range of stellar parameters and compositions, from main sequence to red giant branch and with metallicities from [Fe/H]=+0.5 down to [Fe/H]=-4. I will illustrate the main effects of 3D modelling on the predicted strengths and shapes of spectral lines, highlighting the systematic differences with respect to calculations based on classical, 1D, hydrostatic models.

In particular, I will discuss spectroscopic carbon, nitrogen and oxygen abundance determinations based on the analysis of CH, NH, CN and OH molecular bands with 3D model atmospheres of low-metallicity stars. I will show that the differences with respect to classical analyses based on 1D models can be significant and of the order of 0.5 to 1 dex in terms of logarithmic abundances of these important elements