CEMP Stars as Probes of First-Star Nucleosynthesis, the IMF, and Galactic Assembly

Accurate abundances at the lowest detected iron abundance: SMSS 1605-1443

9 Sept 2019, 11:00

20m

Oral contribution OBSERVATIONAL APPROACH: CEMP STARS, FIRST STARS, FIRST GALAXIES

Speaker

Thomas Nordlander (Australian National University)

Description

We recently announced the discovery of SMSS 1605-1443, which has the lowest detected iron abundance of any star at [Fe/H] = -6.2 (1D LTE). It is strongly carbon enhanced with [C/Fe] ~ 4, but otherwise exhibits a perfectly normal halo star abundance pattern with no detection of neutron capture elements. Assuming a single enrichment event, we find good matches to predictions for Population III stars exploding in low-energy fallback-and-mixing supernovae (from Heger & Woosley 2010) assuming the progenitor star was just 10 solar mass.
I shall discuss recent results from follow-up UVES spectroscopy as well as accurate 3D NLTE spectrum synthesis calculations.