Stars, Planets, and ISM Seminar

Chemical Abundances Reveal the True Nature of the LMS-1 Stellar Stream

The LMS-1 stream represents the only chance locally to study an intact low-mass dwarf galaxy and globular cluster (GC) system. As a low mass dwarf galaxy, it also offers insight into the extreme chemical abundances and rare nucleosynthesis now synonymous with these objects. Currently on a polar orbit, just north of the Galactic Bulge, LMS-1 was likely a major contributor to the build-up of the inner Milky Way at early times and given the close proximity in phase space and metallicity to the globular clusters, NGC 5024 and NGC 5053, it is possible that these clusters were accreted alongside LMS-1. For the first time, we have performed homogeneous abundance measurements of stars in LMS-1, NGC 5024 and NGC 5053 to understand the chemical similarities and differences between the galaxy and its clusters. Using our chemical abundances, we provide further support for an association between the clusters and LMS-1, testing predictions from the GC-halo mass relation at the lowest halo masses. Among the LMS-1 stars, we find a large >1 dex spread in Barium, driven by two extremely neutron-capture process deficient stars - placing further constraints on the total stellar mass of the LMS-1 progenitor galaxy. These results will be interpreted in the context of the accretion history of the Milky Way and more generally, in the context of star formation and evolution at the earliest times.