Issue |
A&A
Volume 627, July 2019
|
|
---|---|---|
Article Number | A178 | |
Number of page(s) | 11 | |
Section | Galactic structure, stellar clusters and populations | |
DOI | https://doi.org/10.1051/0004-6361/201834391 | |
Published online | 22 July 2019 |
H-band discovery of additional second-generation stars in the Galactic bulge globular cluster NGC 6522 as observed by APOGEE and Gaia
1
Instituto de Astronomía y Ciencias Planetarias, Universidad de Atacama, Copayapu 485, Copiapó, Chile
e-mail: jfernandez@obs-besancon.fr
2
Institut Utinam, CNRS UMR 6213, Université Bourgogne-Franche-Comté, OSU THETA Franche-Comté, Observatoire de Besançon, BP 1615, 25010 Besançon Cedex, France
3
Departamento de Astronomía, Casilla 160-C, Universidad de Concepción, Concepción, Chile
4
Instituto de Astrofísica de Canarias, Vía Láctea s/n, 38205 La Laguna, Tenerife, Spain
5
Departamento de Astrofísica, Universidad de La Laguna (ULL), 38206 La Laguna, Tenerife, Spain
6
Observatório Nacional, Rua Gal. José Cristino 77, 20921-400 Rio de Janeiro, Brazil
7
Departamento de Física, Universidade Federal de Sergipe, Av. Marechal Rondon, s/n, 49000-000 São Cristóvão, SE, Brazil
8
Space Telescope Science Institute, 3700 San Martin Dr, Baltimore, MD 21218, USA
9
Astrophysics Research Institute, Liverpool John Moores University, 146 Brownlow Hill, Liverpool L3 5RF, UK
10
ELTE Gothard Astrophysical Observatory, Szent Imre Herceg st., 9704 Szombathely, Hungary
11
Steward Observatory, University of Arizona, 933 North Cherry Avenue, Tucson, AZ 85721, USA
12
New Mexico State University, Las Cruces, NM 88003, USA
13
University of Texas at Austin, McDonald Observatory, Fort Davis, TX 79734, USA
14
School of Physics and Astronomy, Sun Yat-sen University, Zhuhai 519082, PR China
15
Departamento de Física, Facultad de Ciencias, Universidad de La Serena, Cisternas 1200, La Serena, Chile
16
Instituto de Investigación Multidisciplinario en Ciencia y Tecnología, Universidad de La Serena, Avenida Raúl Bitrán s/n, La Serena, Chile
17
Departamento de Fisica, Facultad de Ciencias Exactas, Universidad Andres Bello, Av. Fernandez Concha 700, Las Condes, Santiago, Chile
18
Instituto Milenio de Astrofisica, Santiago, Chile
19
Vatican Observatory, 00120 Vatican City State, Italy
20
Centro de Astronomía (CITEVA), Universidad de Antofagasta, Av. Angamos 601, Antofagasta, Chile
21
Consejo Superior de Investigaciones Científicas, Spain
22
Department of Physics and JINA Center for the Evolution of the Elements, University of Notre Dame, Notre Dame, IN 46556, USA
23
Department of Astronomy, University of Washington, Seattle, WA 98195, USA
24
Department of Physics & Astronomy, University of Utah, Salt Lake City, UT 84112, USA
25
Laboratoire Lagrange, Université Côte d’Azur, Observatoire de la Côte d’Azur, CNRS, Blvd de l’Observatoire, 06304 Nice, France
26
Department of Astronomy, University of Virginia, Charlottesville, VA 22903, USA
27
Instituto de Astrofśica, Pontificia Universidad Católica de Chile, Av. Vicuna Mackenna 4860, 782-0436 Macul, Santiago, Chile
28
Universidad de Chile, Av. Libertador Bernardo O’Higgins 1058, Santiago, Chile
29
Department of Physics & Astronomy, Vanderbilt University, Nashville, TN 37235, USA
30
Department of Physics, University of California, San Diego, CA 92093, USA
31
Department of Astronomy and Astrophysics, The Pennsylvania State University, University Park, PA 16802, USA
Received:
5
October
2018
Accepted:
13
June
2019
We present an elemental abundance analysis of high-resolution spectra for five giant stars spatially located within the innermost regions of the bulge globular cluster NGC 6522 and derive Fe, Mg, Al, C, N, O, Si, and Ce abundances based on H-band spectra taken with the multi-object APOGEE-north spectrograph from the SDSS-IV Apache Point Observatory Galactic Evolution Experiment (APOGEE) survey. Of the five cluster candidates, two previously unremarked stars are confirmed to have second-generation (SG) abundance patterns, with the basic pattern of depletion in C and Mg simultaneous with enrichment in N and Al as seen in other SG globular cluster populations at similar metallicity. In agreement with the most recent optical studies, the NGC 6522 stars analyzed exhibit (when available) only mild overabundances of the s-process element Ce, contradicting the idea that NGC 6522 stars are formed from gas enriched by spinstars and indicating that other stellar sources such as massive AGB stars could be the primary polluters of intra-cluster medium. The peculiar abundance signatures of SG stars have been observed in our data, confirming the presence of multiple generations of stars in NGC 6522.
Key words: stars: abundances / stars: Population II / globular clusters: individual: NGC 6522 / Galaxy: formation / Galaxy: structure
© J. G. Fernández-Trincado et al. 2019
Open Access article, published by EDP Sciences, under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
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