Extending the chemical reach of the H3 survey: Detailed abundances of the dwarf-galaxy stellar stream Wukong/LMS-1

Guilherme Limberg, Alexander P. Ji, Rohan P. Naidu, Anirudh Chiti, Silvia Rossi, Sam A. Usman, Yuan Sen Ting, Dennis Zaritsky, Ana Bonaca, Lais Borbolato, Joshua S. Speagle, Vedant Chandra, Charlie Conroy

Research output: Contribution to journalArticlepeer-review

1 Scopus citations

Abstract

We present the first detailed chemical-Abundance analysis of stars from the dwarf-galaxy stellar stream Wukong/LMS-1 covering a wide metallicity range (). We find abundance patterns that are effectively indistinguishable from the bulk of Indus and Jhelum, a pair of smaller stellar streams proposed to be dynamically associated with Wukong/LMS-1. We confirmed a carbon-enhanced metal-poor star (and) in Wukong/LMS-1 with strong enhancements in Sr, Y, and Zr, which is peculiar given its solar-level [Ba/Fe]. Wukong/LMS-1 stars have high abundances of α elements up to, which is expected for relatively massive dwarfs. Towards the high-metallicity end, Wukong/LMS-1 becomes α-poor, revealing that it probably experienced fairly standard chemical evolution. We identified a pair of N-and Na-rich stars in Wukong/LMS-1, reminiscent of multiple stellar populations in globular clusters. This indicates that this dwarf galaxy contained at least one globular cluster that was completely disrupted in addition to two intact ones previously known to be associated with Wukong/LMS-1, which is possibly connected to similar evidence found in Indus. From these ≥3 globular clusters, we estimate the total mass of Wukong/LMS-1 to be, representing ∼1 per cent of the present-day Milky Way. Finally, the [Eu/Mg] ratio in Wukong/LMS-1 continuously increases with metallicity, making this the first example of a dwarf galaxy where the production of r-process elements is clearly dominated by delayed sources, presumably neutron-star mergers.

Original languageEnglish (US)
Pages (from-to)2512-2525
Number of pages14
JournalMonthly Notices of the Royal Astronomical Society
Volume530
Issue number3
DOIs
StatePublished - May 1 2024

Keywords

  • Galaxy: halo
  • Galaxy: kinematics and dynamics
  • Local Group
  • galaxies: dwarf
  • stars: Abundances

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science

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