Title

An extremely metal-deficient globular cluster in the Andromeda Galaxy

Publication Date

11-20-2020

Document Type

Article

Department

Physics and Astronomy

Publication Title

Science

Volume

370

Issue

6519

DOI

10.1126/science.abb1970

First Page

970

Last Page

973

Abstract

Globular clusters (GCs) are dense, gravitationally bound systems of thousands to millions of stars. They are preferentially associated with the oldest components of galaxies, so measurements of their composition can constrain the build-up of chemical elements in galaxies during the early Universe.We report a massive GC in the Andromeda Galaxy (M31), RBC EXT8, that is extremely depleted in heavy elements. Its iron abundance is about 1/800 that of the Sun and about one-third that of the most iron-poor GCs previously known. It is also strongly depleted in magnesium. These measurements challenge the notion of a metallicity floor for GCs and theoretical expectations that massive GCs could not have formed at such low metallicities.

Funding Number

1748958

Funding Sponsor

National Science Foundation

Share

COinS