Affiliation

SAC, Aarhus University and DARK, Niels Bohr Institute, Copenhagen University

Main category

Natural Sciences (Astrophysics and Astrononmy)

Abstract

Extremely metal-poor (EMP) halo stars with [Fe/H] below ~ -3 are considered to be fossil records of conditions in the early halo. In the naïve picture in which iron is a proxy for overall metallicity and indirectly for time, EMP stars formed well before the Galactic globular clusters. Their detailed abundance pattern is very uniform and essentially scaled Solar, except for the α-enhancement typical of halo stars. A minority are, however, dramatically enhanced in carbon (C) and/or r-process elements, with or without a concomitant excess of s-process elements (CEMP-n and CEMP-s stars). How were these elements produced – as a surface contamination deposited locally by a binary companion or far away in the early Galaxy? Are these stars mostly binaries; if so, does it matter? If not, how were the excess elements implanted in the natal clouds of the stars we see today? The

Link this poster

https://science-media.org/poster/58