# 2017 JINA-CEE Frontiers in Nuclear Astrophysics

Feb 7 – 9, 2017
US/Eastern timezone

## Ultra metal-poor stars: Non-LTE abundances

Feb 7, 2017, 4:45 PM
1h 15m

111 N Grand Ave, Lansing, MI 48933
Poster [Main Conference]

### Speaker

Dr Rana Ezzeddine (MIT)

### Description

Ancient ultra-metal-poor (UMP) stars are rare relics of the early Universe. They provide unique insights into the first nucleosynthesis events and the formation of the first (Pop III) stars. Detailed comparisons of supernova (SN) nucleosynthesis yields with UMP stellar abundances allow us to constrain the nature and shape of the initial mass function (IMF) of Pop III stars. We present new (UMP) stars abundance study of the most iron poor stars known to date (with [Fe/H] <-4.00) using a full line-by-line Non Local Thermodynamic Equilibrium (NLTE) analysis for Fe and $alpha$-elements. We show that our NLTE corrections for Fe can be extended to at least [Fe/H] = -2.00, showing agreement with independent NLTE determinations. We emphasize that the UMP stars can suffer from large NLTE effects for all these elements, which can potentially affect and alter the presently known (IMF) of Pop III stars determined from previous LTE studies.

### Primary author

Dr Rana Ezzeddine (MIT)

### Co-authors

Prof. Anna Frebel (Massachusetts Institute of Technology) Prof. Bertrand Plez (Universite de Montpellier)

### Presentation materials

There are no materials yet.