2007A&A...464..953G


C.D.S. - SIMBAD4 rel 1.7 - 2020.10.25CET09:23:16

2007A&A...464..953G - Astronomy and Astrophysics, volume 464, 953-965 (2007/3-4)

Na-O anticorrelation and horizontal branches. V. The Na-O anticorrelation in NGC 6441 from Giraffe spectra.

GRATTON R.G., LUCATELLO S., BRAGAGLIA A., CARRETTA E., CASSISI S., MOMANY Y., PANCINO E., VALENTI E., CALOI V., CLAUDI R., D'ANTONA F., DESIDERA S., FRANCOIS P., JAMES G., MOEHLER S., ORTOLANI S., PASQUINI L., PIOTTO G. and RECIO-BLANCO A.

Abstract (from CDS):

We present an analysis of FLAMES-Giraffe spectra for several bright giants in NGC 6441, to investigate the presence and extent of the Na-O anticorrelation in this anomalous globular cluster. The field of NGC 6441 is very crowded, with severe contamination by foreground (mainly bulge) field stars. Appropriate membership criteria were devised to identify a group of 25 likely cluster members among the about 130 stars observed. Combined with the UVES data obtained with the same observations (Gratton et al., 2006A&A...455..271G), high dispersion abundance analyses are now available for a total of 30 stars in NGC 6441, 29 of them having data for both O and Na. The spectra were analyzed by a standard line analysis procedure; care was taken to minimize the impact of the differential interstellar reddening throughout the cluster, and to extract reliable information from crowded, and moderately high S/N (30-70), moderately high resolution (R∼23000) spectra. NGC 6441 has the typical abundance pattern seen in several other globular clusters. It is very metal-rich ([Fe/H]=-0.34±0.02±0.04dex). There is no clear sign of star-to-star scatter in the Fe-peak elements. The α-elements Mg, Si, Ca, and Ti are overabundant by rather large factors, suggesting that the cluster formed from material enriched by massive core collapse SNe. The O-Na anticorrelation is well defined, with about 1/4 of the stars being Na-rich and O-poor. One of the stars is a Ba-rich and moderately C-rich star. Such stars are rare in globular clusters.The distribution of [Na/O] ratios among RGB stars in NGC 6441 appears similar to the distribution of colors of stars along the horizontal branch. The fraction of Na-poor, O-rich stars found in NGC 6441 agrees well with that of stars on the red horizontal branch of this cluster (in both cases about 80%), with a sloping distribution toward lower values of [O/Na] (among RGB stars) and bluer colors (among HB stars).

Abstract Copyright:

Journal keyword(s): stars: abundances - stars: atmospheres - stars: Population II - Galaxy: globular clusters: general - Galaxy: globular clusters: individual: NGC 6441

VizieR on-line data: <Available at CDS (J/A+A/464/953): table2.dat table3.dat>

Nomenclature: Table 2: Cl* NGC 6441 GLB NNNNNNN N=25 among (Nos 6005198-8013657).

Simbad objects: 32

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Number of rows : 32

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 104 GlC 00 24 05.359 -72 04 53.20   5.78 4.09     ~ 3575 0
2 NAME LMC G 05 23 34.6 -69 45 22     0.4     ~ 14993 1
3 NGC 2808 GlC 09 12 03.10 -64 51 48.6   7.77 5.69     ~ 1254 0
4 NGC 6388 GlC 17 36 17.461 -44 44 08.34   7.40       ~ 810 1
5 Cl* NGC 6441 GLB 6005198 * 17 49 30.1691277472 -37 05 18.751264865     16.274   13.947 ~ 1 0
6 Cl* NGC 6441 GLB 6005934 * 17 49 32.2 -37 12 04     16.387   14.402 ~ 1 0
7 Cl* NGC 6441 GLB 6012768 * 17 49 43.7 -37 11 32     17.043   14.938 ~ 1 0
8 Cl* NGC 6441 GLB 6010149 * 17 49 45.7996888810 -37 08 09.839397402     16.842   14.728 ~ 1 0
9 Cl* NGC 6441 GLB 6007741 * 17 49 48.49 -37 00 20.3     16.612   14.557 ~ 1 0
10 Cl* NGC 6441 GLB 7006590 * 17 49 59.1 -37 01 25     16.475   14.598 ~ 1 0
11 Cl* NGC 6441 GLB 7006377 * 17 50 03.1 -37 08 02     16.445   14.34 ~ 1 0
12 Cl* NGC 6441 GLB 7006319 * 17 50 03.89 -37 03 39.0     16.438   14.463 ~ 1 0
13 Cl* NGC 6441 GLB 7007118 * 17 50 05.8185301481 -36 58 05.694504455     16.542   14.564 ~ 1 0
14 Cl* NGC 6441 GLB 7006935 * 17 50 08.74 -36 56 33.4     16.518   14.375 ~ 1 0
15 Cl* NGC 6441 GLB 7006255 * 17 50 09.9 -37 03 55     16.430   14.432 ~ 1 0
16 NGC 6441 GlC 17 50 13.06 -37 03 05.2   9.26 8.00     ~ 772 0
17 Cl* NGC 6441 GLB 7006470 * 17 50 13.7 -36 58 01     16.458   14.512 ~ 1 0
18 Cl* NGC 6441 GLB 7006354 * 17 50 15.1640826138 -37 06 17.610714700     16.442   14.181 ~ 1 0
19 Cl* NGC 6441 GLB 7008891 * 17 50 16.2 -37 00 15     16.730   14.741 ~ 1 0
20 Cl* NGC 6441 GLB 7007884 * 17 50 18.3805838182 -37 05 18.197284111     16.631   14.570 ~ 1 0
21 Cl* NGC 6441 GLB 7004955 * 17 50 19.45 -37 00 44.7     16.232   14.068 ~ 1 0
22 Cl* NGC 6441 GLB 7007064 * 17 50 22.9539024026 -37 02 50.253698113     16.535   14.231 ~ 1 0
23 Cl* NGC 6441 GLB 7006305 * 17 50 30.4 -37 00 52     16.437   14.325 ~ 1 0
24 Cl* NGC 6441 GLB 7013582 * 17 50 33.7 -36 59 23     17.097   14.952 ~ 1 0
25 Cl* NGC 6441 GLB 7006983 * 17 50 33.94 -36 56 27.0     16.522   14.447 ~ 1 0
26 Cl* NGC 6441 GLB 8006535 * 17 50 39.85 -36 58 54.7     16.467   14.227 ~ 1 0
27 Cl* NGC 6441 GLB 8008693 * 17 50 45.5022075658 -36 59 23.715696413     16.711   14.439 ~ 1 0
28 Cl* NGC 6441 GLB 8005404 * 17 50 47.3678181267 -37 08 30.501674611     16.306   14.078 ~ 1 0
29 Cl* NGC 6441 GLB 8013657 * 17 50 54.7205191482 -37 10 13.328214641     17.103   14.992 ~ 1 0
30 Cl* NGC 6441 GLB 8005158 * 17 50 58.5 -36 59 12     16.267   14.254 ~ 1 0
31 NGC 6752 GlC 19 10 52.11 -59 59 04.4   6.96 6.28     ~ 1817 0
32 M 71 GlC 19 53 46.49 +18 46 45.1   7.91 6.1     ~ 1028 0

    Equat.    Gal    SGal    Ecl

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2020.10.25-09:23:16

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