APOGEE discovery of a chemically atypical star disrupted from NGC 6723 and captured by the Milky Way bulge

The central ('bulge') region of the Milky Way is teeming with a significant fraction of mildly metal-deficient stars with atmospheres that are strongly enriched in cyanogen (12C14N). Some of these objects, which are also known as nitrogen-enhanced stars, are hypothesised to be relics of the ancient assembly history of the Milky Way. Although the chemical similarity of nitrogen-enhanced stars to the unique chemical patterns observed in globular clusters has been observed, a direct connection between field stars and globular clusters has not yet been proven. In this work, we report on high-resolution, near-infrared spectroscopic observations of the bulge globular cluster NGC 6723, and the serendipitous discovery of a star, 2M18594405-3651518, located outside the cluster (near the tidal radius) but moving on a similar orbit, providing the first clear piece of evidence of a star that was very likely once a cluster member and has recently been ejected. Its nitrogen abundance ratio ([N/Fe] + 0.94) is well above the typical Galactic field-star levels, and it exhibits noticeable enrichment in the heavy s-process elements (Ce, Nd, and Yb), along with moderate carbon enrichment; all characteristics are known examples in globular clusters. This result suggests that some of the nitrogen-enhanced stars in the bulge likely originated from the tidal disruption of globular clusters.Fil: Fernández Trincado, José G.. Universidad de Atacama.; Chile. Universite de Franche-Comte; Francia. University of Notre Dame; Estados UnidosFil: Beers, Timothy. University of Notre Dame; Estados UnidosFil: Minniti, Dante. Universidad Andrés Bello; Chile. Vatican Observatory; Ciudad del VaticanoFil: Carigi, Leticia. Universidad Nacional Autónoma de México; MéxicoFil: Placco, Vinivius M.. NSF’s National Optical-Infrared Astronomy Research Laboratory; Estados UnidosFil: Chun, Sang Hyun. Korea Astronomy And Space Science Institute; Corea del SurFil: Lane, Richard R.. Universidad de Atacama.; ChileFil: Geisler, Doug. Universidad de La Serena; Chile. Universidad de Concepción; ChileFil: Villanova, Sandro. Universidad de Concepción; ChileFil: Souza, Stefano O.. Universidade de Sao Paulo; BrasilFil: Barbuy, Beatriz. Universidade de Sao Paulo; BrasilFil: Pérez Villegas, Angeles. Universidad Nacional Autónoma de México; MéxicoFil: Chiappini, Cristina. Leibniz-Institut für Astrophysik Potsdam; Alemania. Laboratório Interinstitucional de e-Astronomia; BrasilFil: Queiroz, Anna B. A.. Leibniz-Institut für Astrophysik Potsdam; AlemaniaFil: Tang, Baitian. Sun Yat-sen University; ChinaFil: Alonso García, Javier. Universidad de Antofagasta; Chile. Millennium Institute of Astrophysics; ChileFil: Piatti, Andres Eduardo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza. Instituto Interdisciplinario de Ciencias Básicas. - Universidad Nacional de Cuyo. Instituto Interdisciplinario de Ciencias Básicas; ArgentinaFil: Palma, Tali. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de Córdoba. Observatorio Astronómico de Córdoba. Departamento de Astrofísica Estelar; ArgentinaFil: Alves Brito, Alan. Universidade Federal do Rio Grande do Sul; BrasilFil: Moni Bidin, Christian. Universidad Católica del Norte; ChileFil: Roman Lopes, Alexandre. Universidad de La Serena; ChileFil: Muñoz, Richard R.. Universidad de Chile; Chile. National Optical Astronomy Observatory. Cerro Tololo Inter-American Observatory; ChileFil: Singh, Harinder P.. University Of Delhi; IndiaFil: Kundu, Richa. University Of Delhi; India. European Southern Observatory; ChileFil: Chaves Velasquez, Leonardo. Universidad de Nariño; ColombiaFil: Romero Colmenares, María. Universidad de Antofagasta; ChileFil: Longa Peña, Penelope. Universidad de Antofagasta; ChileFil: Soto, Mario. Universidad de Atacama; ChileFil: Vieira, Katherine. Universidad de Atacama; Chil