A Status Report on the 0Z Project

TL;DR

This paper reports on the progress of the 0Z Survey, which analyzes metal-poor stars in the Galactic halo using high-resolution spectra, discovering new stars with extremely low metallicity and examining their chemical abundance patterns.

Contribution

It provides the first detailed abundance analyses of a large sample of extremely metal-poor stars from the 0Z Survey, including new discoveries and insights into chemical anomalies.

Findings

Discovered 18 stars with [Fe/H] < -3.5 dex

Identified 57 stars with [Fe/H] < -3.0 dex

Approximately 15% of the sample show chemical anomalies

Abstract

We present an update on the status of the 0Z Survey, an effort to datamine the Hamburg/ESO Survey to find and study in detail a large sample of extremely metal-poor Galactic halo field stars with [Fe/H] < -3 dex. After searching 1,565 moderate resolution spectra of candidates selected from the HES, we have acquired high resolution spectra of 103 of the most metal-poor of them. Detailed abundance analyses have been performed for all these stars. This has resulted in the discovery of 18 new stars below [Fe/H] -3.5 dex and 57 below -3.0 dex. Some results are presented regarding our search for outliers in chemical abundances of particular species among the sample of 103 stars. Ignoring C and N, about 15% of the sample are "abnormal" in some way. Our plans to complete this project and write the final set of papers are described.