TY - JOUR
T1 - NGC 6139: a normal massive globular cluster, or a first-generation dominated cluster? Clues from the light elements
AU - Bragaglia, A
AU - Carretta, E
AU - Sollima, A
AU - Donati, P
AU - D'Orazi, V
AU - Gratton, R G
AU - Lucatello, S
AU - Sneden, C
PY - 2015
Y1 - 2015
N2 - Information on globular clusters (GC) formation mechanisms can be gathered by studying the chemical signature of the multiple populations that compose these stellar systems. In particular, we investigate the anti-correlations among O, Na, Al, and Mg to explore the influence of cluster mass and environment on GCs in the Milky Way and in extragalactic systems. We present here the results obtained on NGC 6139, which, on the basis of its horizontal branch morphology, has been proposed to be dominated by first-generation stars. In our extensive study based on high-resolution spectroscopy, the first for this cluster, we found a metallicity of [Fe/H] = -1.579 ± 0.015 ± 0.058 (rms = 0.040 dex, 45 bona fide member stars) on the UVES scale defined by our group. The stars in NGC 6139 show a chemical pattern normal for GCs, with a rather extended Na-O (and Mg-Al) anti correlation. NGC 6139 behaves as expected from its mass and contains a large portion (about two thirds) of second-generation stars.
AB - Information on globular clusters (GC) formation mechanisms can be gathered by studying the chemical signature of the multiple populations that compose these stellar systems. In particular, we investigate the anti-correlations among O, Na, Al, and Mg to explore the influence of cluster mass and environment on GCs in the Milky Way and in extragalactic systems. We present here the results obtained on NGC 6139, which, on the basis of its horizontal branch morphology, has been proposed to be dominated by first-generation stars. In our extensive study based on high-resolution spectroscopy, the first for this cluster, we found a metallicity of [Fe/H] = -1.579 ± 0.015 ± 0.058 (rms = 0.040 dex, 45 bona fide member stars) on the UVES scale defined by our group. The stars in NGC 6139 show a chemical pattern normal for GCs, with a rather extended Na-O (and Mg-Al) anti correlation. NGC 6139 behaves as expected from its mass and contains a large portion (about two thirds) of second-generation stars.
KW - Galaxy: general
KW - Globular clusters: general
KW - Globular clusters: individual
KW - NGC 6139
KW - Stars: abundances
KW - Stars: atmospheres
KW - Stars: Population II
UR - http://www.aanda.org/articles/aa/pdf/2015/11/aa26592-15.pdf
U2 - 10.1051/0004-6361/201526592
DO - 10.1051/0004-6361/201526592
M3 - Article
SN - 0004-6361
VL - 583
SP - 1
EP - 9
JO - Astronomy & Astrophysics
JF - Astronomy & Astrophysics
M1 - A69
ER -