2012A&A...540A...3A


C.D.S. - SIMBAD4 rel 1.7 - 2019.12.13CET15:16:25

2012A&A...540A...3A - Astronomy and Astrophysics, volume 540A, 3-3 (2012/4-1)

CNO and F abundances in the globular cluster M 22 (NGC 6656).

ALVES-BRITO A., YONG D., MELENDEZ J., VASQUEZ S. and KARAKAS A.I.

Abstract (from CDS):

Recent studies have confirmed the long standing suspicion that M22 shares a metallicity spread and complex chemical enrichment history similar to that observed in ω Cen. M22 is among the most massive Galactic globular clusters and its color-magnitude diagram and chemical abundances reveal the existence of sub-populations. To further constrain the chemical diversity of M22, necessary to interpret its nucleosynthetic history, we seek to measure relative abundance ratios of key elements (carbon, nitrogen, oxygen, and fluorine) best studied, or only available, using high-resolution spectra at infrared wavelengths. High-resolution (R=50000) and high S/N infrared spectra were acquired of nine red giant stars with Phoenix at the Gemini-South telescope. Chemical abundances were calculated through a standard 1D local thermodynamic equilibrium analysis using Kurucz model atmospheres. We derive [Fe/H]=-1.87 to -1.44, confirming at infrared wavelengths that M22 does present a [Fe/H] spread. We also find large C and N abundance spreads, which confirm previous results in the literature but based on a smaller sample. Our results show a spread in A(C+N+O) of ∼0.7dex. Similar to mono-metallic globular clusters, M22 presents a strong [Na/Fe]-[O/Fe] anticorrelation as derived from Na and CO lines in the K band. For the first time we recover F abundances in M22 and find that it exhibits a 0.6dex variation. We find tentative evidence for a flatter A(F)-A(O) relation compared to higher metallicity globular clusters. Our study confirms and expands upon the chemical diversity seen in this complex stellar system. All elements studied to date show large abundance spreads which require contributions from both massive and low mass stars.

Abstract Copyright:

Journal keyword(s): Galaxy: abundances - globular clusters: individual: M22 (NGC 6656) - stars: abundances

Simbad objects: 17

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Number of rows : 17

N Identifier Otype ICRS (J2000)
RA
ICRS (J2000)
DEC
Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2020
#notes
1 NGC 1851 GlC 05 14 06.76 -40 02 47.6   8.80 7.23     ~ 1215 0
2 NGC 5139 GlC 13 26 47.28 -47 28 46.1   6.12 5.33     ~ 2923 0
3 M 4 GlC 16 23 35.22 -26 31 32.7           ~ 1640 0
4 NAME Gal Center reg 17 45 40.04 -29 00 28.1           ~ 11090 0
5 Cl* NGC 6656 ALC 2009 * 18 36 08.1951849568 -23 55 02.858722781   13.24 11.13     G2 17 0
6 NGC 6656 3052 * 18 36 10.1882767604 -23 54 22.152554850   13.2488 11.5217   9.6761 ~ 33 0
7 Cl* NGC 6656 ALC 1022 * 18 36 10.5797771116 -23 55 00.524380251   12.02 10.97     G0 19 0
8 NGC 6656 3012 * 18 36 14.2692059727 -23 54 31.406960324   13.236 11.540   9.723 ~ 23 0
9 NGC 6656 3014 * 18 36 15.1039678940 -23 54 54.907720434   12.40 10.93   9.145 ~ 19 0
10 NGC 6656 3015 * 18 36 15.6177474637 -23 55 01.582871876   13.057 11.362   9.484 ~ 12 0
11 NGC 6656 2096 * 18 36 17.2423670215 -23 54 11.608145049   13.134 11.604   9.879 ~ 7 0
12 NGC 6656 3003 * 18 36 17.5181798833 -23 54 26.585866022   12.8797 11.0304   9.0975 ~ 30 0
13 M 22 GlC 18 36 23.94 -23 54 17.1   7.16 6.17     ~ 1182 0
14 NGC 6656 1092 * 18 36 33.2884944136 -23 52 32.860164519   13.141 11.561   9.828 ~ 27 0
15 NGC 6656 4102 * 18 36 36.1972617629 -23 59 39.470209756   12.70 11.17   9.111 ~ 27 0
16 NGC 6656 4097 * 18 36 41.0627598387 -23 58 19.487901177   12.799 10.9295   8.9453 ~ 37 0
17 NGC 6712 GlC 18 53 04.32 -08 42 21.5   9.85 8.69     ~ 460 0

    Equat.    Gal    SGal    Ecl

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2019.12.13-15:16:25

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