| Issue |
A&A
Volume 688, August 2024
|
|
|---|---|---|
| Article Number | A154 | |
| Number of page(s) | 8 | |
| Section | Galactic structure, stellar clusters and populations | |
| DOI | https://doi.org/10.1051/0004-6361/202450556 | |
| Published online | 14 August 2024 | |
Detailed chemical abundances of the globular cluster Terzan 6 in the inner bulge⋆
1
INAF, Osservatorio di Astrofisica e Scienza dello Spazio di Bologna, Via Gobetti 93/3, 40129 Bologna, Italy
e-mail: cristiano.fanelli@inaf.it
2
Dipartimento di Fisica e Astronomia, Università degli Studi di Bologna, Via Gobetti 93/2, 40129 Bologna, Italy
3
Department of Physics and Astronomy, UCLA, 430 Portola Plaza, Box 951547 Los Angeles, CA 90095-1547 } USA
Received:
30
April
2024
Accepted:
28
May
2024
We used near-infrared spectroscopy at medium-high resolution (R = 8000 − 25 000) to perform the first comprehensive chemical study of the intermediate luminosity bulge globular cluster Terzan 6. We derived detailed abundances and abundance patterns of 27 giant stars, likely members of Terzan 6, based on their accurate Hubble Space Telescope proper motions and line-of-sight radial velocities. From the spectral analysis of these stars, we determined an average heliocentric radial velocity of 143.3 ± 1.0 km s−1 with a velocity dispersion of 5.1 ± 0.7 km s−1 and an average [Fe/H] = −0.65 ± 0.01 and a low 1σ dispersion of 0.03 dex. We also measured some depletion of [Mn/Fe] with respect to the solar-scaled values and enhancement of for [Ca/Fe], [Si/Fe], [Mg/Fe], [Ti/Fe], [O/Fe], [Al/Fe], [Na/Fe], and, to a lower extent, for [K/Fe], consistent with previous measurements of other bulge globular clusters and favoring the scenario of a rapid bulge formation and chemical enrichment. Some spread in the light element abundances suggest the presence of first- and second-generation stars, typical of genuine globulars. Finally, we measured some depletion of carbon and low 12C/13C isotopic ratios, as in previous studies of field and cluster bulge giants, indicating that extra-mixing mechanisms should be at work during the post main sequence evolution in the high metallicity regime as well.
Key words: techniques: spectroscopic / stars: abundances / stars: late-type / Galaxy: bulge
Based on observations collected at the W. M. Keck Observatory, which is operated as a scientific partnership among the California Institute of Technology, the University of California, and the National Aeronautics and Space Administration. The Observatory was made possible by the generous financial support of the W. M. Keck Foundation. Also based on observations at the Very Large Telescope of the European Southern Observatory at Cerro Paranal (Chile) under program 089.D-0306 (PI:Ferraro).
© The Authors 2024
Open Access article, published by EDP Sciences, under the terms of the Creative Commons Attribution License (https://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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