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

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Fernandez-Trincado, Jose G. ^{[1, 2, 3]} ; Beers, Timothy C. ^{[4, 5]} ; Minniti, Dante ^{[6, 7]} ; Carigi, Leticia ^[8] ; Placco, Vinicius M. ^[9] ; Chun, Sang-Hyun ^[10] ; Lane, Richard R. ^[1] ; Geisler, Doug ^{[11, 12, 13]} ; Villanova, Sandro ^[11] ; Souza, Stefano O. ^[14] ; Barbuy, Beatriz ^[14] ; Perez-Villegas, Angeles ^[15] ; Chiappini, Cristina ^{[16, 17]} ; Queiroz, Anna. B. A. ^[16] ; Tang, Baitian ^[18] ; Alonso-Garcia, Javier ^{[19, 20]} ; Piatti, Andres E. ^{[21, 22]} ; Palma, Tali ^{[23, 24]} ; Alves-Brito, Alan ^[25] ; Bidin, Christian Moni ^[26] ; Roman-Lopes, Alexandre ^[12] ; Munoz, Ricardo R. ^[27] ; Singh, Harinder P. ^[28] ; Kundu, Richa ^{[28, 29]} ; Chaves-Velasquez, Leonardo ^{[30, 31]} ; Romero-Colmenares, Maria ^[20] ; Longa-Pena, Penelope ^[20] ; Soto, Mario ^[1] ; Vieira, Katherine ^[1]

Afiliação do(s) autor(es):Mostrar menos -

^[1] Univ Bourgogne Franche Comte, Inst Utinam, CNRS UMR 6213, OSU THETA Franche Comte, Observ Besancon, BP 1615, F-25010 Besancon - France

^[2] Univ Atacama, Inst Astron & Ciencias Planetarias, Copayapu 485, Copiapo - Chile

^[3] Univ Bernardo OHiggins, Ctr Invest Astron, Ave Viel 1497, Santiago - Chile

^[4] Univ Notre Dame, Dept Phys, Notre Dame, IN 46556 - USA

^[5] Univ Notre Dame, JINA Ctr Evolut Elements, Notre Dame, IN 46556 - USA

^[6] Vatican Observ, I-00120 Vatican City - Vatican

^[7] Univ Andres Bello, Dept Cs Fis, Fac Ciencias Exactas, Ave Fernandez Concha 700, Santiago - Chile

^[8] Univ Nacl Autonoma Mexico, Inst Astron, AP 70-264, Mexico City 04510, DF - Mexico

^[9] NSFs Natl Opt Infrared Astron Res Lab, Tucson, AZ 85719 - USA

^[10] Korea Astron & Space Sci Inst, 776 Daedeokdae Ro, Daejeon 34055 - South Korea

^[11] Univ Concepcion, Dept Astron, Casilla 160-C, Concepcion - Chile

^[12] Univ La Serena, Dept Astron, La Serena 1700000 - Chile

^[13] Univ La Serena, Inst Invest Multidisciplinario Ciencia & Tecn, Benavente 980, La Serena - Chile

^[14] Univ Sao Paulo, IAG, Rua Matao 1226, Cidade Univ, BR-05508900 Sao Paulo - Brazil

^[15] Univ Nacl Autonoma Mexico, Inst Astron, Apdo Postal 106, Ensenada 22800, BC - Mexico

^[16] Leibniz Inst Astrophys Potsdam AIP, Sternwarte 16, D-14482 Potsdam - Germany

^[17] Lab Interinst & Astron LIneA, Rua Gal Jose Cristino 77, BR-20921400 Rio De Janeiro, RJ - Brazil

^[18] Sun Yat Sen Univ, Sch Phys & Astron, Zhuhai 519082 - Peoples R China

^[19] Millennium Inst Astrophys, Santiago - Chile

^[20] Univ Antofagasta, Ctr Astron CITEVA, Ave Angamos 601, Antofagasta - Chile

^[21] Consejo Nacl Invest Cient & Tecn CONICET, Godoy Cruz 2290, C1425FQB, Buenos Aires, DF - Argentina

^[22] CONICET UNCUYO, Inst Interdisciplinario Ciencias Basicas ICB, Padre J Contreras 1300, M5502JMA, Mendoza - Argentina

^[23] Consejo Nacl Invest Cient & Tecn CONICET, Godoy Cruz 2290, Buenos Aires, DF - Argentina

^[24] Univ Nacl Cordoba, Observ Astron Cordoba, Laprida 854, RA-5000 Cordoba - Argentina

^[25] Univ Fed Rio Grande do Sul, Inst Fis, Ave Bento Goncalves 9500, Porto Alegre, RS - Brazil

^[26] Univ Catolica Norte, Inst Astron, Ave Angamos 0610, Antofagasta - Chile

^[27] Univ Chile, Dept Astron, Camino Observ 1515, Santiago - Chile

^[28] Univ Delhi, Dept Phys & Astrophys, Delhi 110007 - India

^[29] European Southern Observ, Alonso Cordova 3107, Santiago 7630000 - Chile

^[30] Univ Narino, Univ Narino Observ, Sede VIIS, Ave Panamer, Narino - Colombia

^[31] Univ Narino, Dept Fis, Torobajo Calle 18 Carrera 50, Narino - Colombia

• Tipo de documento: Artigo Científico
• Fonte: Astronomy & Astrophysics; v. 647, MAR 11 2021.
• Citações Web of Science: 1

Resumo

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 ((CN)-C-12-N-14). 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] greater than or similar to +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. (AU)

• Processo FAPESP: 18/22044-3 - Aglomerados globulares do bojo: relíquias da formação e evolução da galáxia
• Beneficiário: Stefano Oliveira de Souza
• Modalidade de apoio: Bolsas no Brasil - Doutorado Direto