Carbon-enhanced metal-poor 3D model atmospheres

TL;DR

This paper introduces new 3D model atmospheres for carbon-enhanced metal-poor stars, highlighting significant 3D effects on spectral features and abundance determinations compared to traditional 1D models.

Contribution

The study provides the first 3D models for CEMP stars and quantifies the impact of 3D effects on spectral line analysis and elemental abundance corrections.

Findings

3D effects cause up to -0.5 dex correction in carbon abundance.

3D models show up to -0.7 dex correction in oxygen abundance.

Significant differences between 3D and 1D spectral syntheses for CEMP stars.

Abstract

We present our latest 3D model atmospheres for carbon-enhanced metal-poor (CEMP) stars computed with the CO5BOLD code. The stellar parameters are representative of hot turn-off objects (Teff ~ 6250 K, log g=4.0, [Fe/H]=-3.0). The main purpose of these models is to investigate the role of 3D effects on synthetic spectra of the CH G-band (4140-4400 A), the CN BX-band (3870-3890 A), and several UV OH transitions (3122-3128 A). By comparison with the synthetic spectra from standard 1D model atmospheres (assuming local thermodynamic equilibrium, LTE), we derive 3D abundance corrections for carbon and oxygen of up to -0.5 and -0.7 dex, respectively.