Fernández-Trincado, J. G.; Zamora, O.; Souto, Diogo; Cohen, R. E.; Dell'Agli, F.; García-Hernández, D. A.; Masseron, T.; Schiavon, R. P.; Mészáros, Sz.; Cunha, K.; Hasselquist, S.; Shetrone, M.; Schiappacasse Ulloa, J.; Tang, B.; Geisler, D.; Schleicher, D. R. G.; Villanova, S.; Mennickent, R. E.; Minniti, D.; Alonso-García, J.; Manchado, A.; Beers, T. C.; Sobeck, J.; Zasowski, G.; Schultheis, M.; Majewski, S. R.; Rojas-Arriagada, A.; Almeida, A.; Santana, F.; Oelkers, R. J.; Longa-Peña, P.; Carrera, R.; Burgasser, A. J.; Lane, R. R.; Roman-Lopes, A.; Ivans, I. I.; Hearty, F. R.
Bibliographical reference
Astronomy and Astrophysics, Volume 627, id.A178, 11 pp.
Description
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.
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