J/ApJ/824/73 Abundances of NGC 6362 member stars (Mucciarelli+, 2016)
NGC 6362: the least massive globular cluster with chemically
distinct multiple populations.
Mucciarelli A., Dalessandro E., Massari D., Bellazzini M., Ferraro F.R.,
Lanzoni B., Lardo C., Salaris M., Cassisi S.
<Astrophys. J., 824, 73-73 (2016)>
=2016ApJ...824...73M 2016ApJ...824...73M (SIMBAD/NED BibCode)
ADC_Keywords: Clusters, globular ; Abundances ; Spectroscopy ; Photometry, UBV
Keywords: globular clusters: NGC 6362;
stars: abundances; techniques: spectroscopic
Abstract:
We present the first measure of Fe and Na abundances in NGC 6362, a
low-mass globular cluster (GC) where first- and second-generation
stars are fully spatially mixed. A total of 160 member stars (along
the red giant branch (RGB) and the red horizontal branch (RHB)) were
observed with the multi-object spectrograph FLAMES at the Very Large
Telescope. We find that the cluster has an iron abundance of
[Fe/H]=-1.09±0.01dex, without evidence of intrinsic dispersion. On
the other hand, the [Na/Fe] distribution turns out to be intrinsically
broad and bimodal. The Na-poor and Na-rich stars populate,
respectively, the bluest and the reddest RGBs detected in the
color-magnitude diagrams including the U filter. The RGB is composed
of a mixture of first- and second-generation stars in a similar
proportion, while almost all the RHB stars belong to the first cluster
generation. To date, NGC 6362 is the least massive GC where both the
photometric and spectroscopic signatures of multiple populations have
been detected.
Description:
A total of 219 stars have been selected along the RGB and the red
horizontal branch (RHB) from the ACS@HST and WFI@2.2m ESO catalogs
presented in Paper I (Dalessandro et al. 2014ApJ...791L...4D 2014ApJ...791L...4D).
The observations have been performed with the multiplex facility
FLAMES@ESO-VLT in the UVES+GIRAFFE combined mode (PID:093.D-0618,
PI:Dalessandro). The employed gratings are the UVES Red Arm CD#3 580,
which covers the spectral range between ∼4800 and ∼6800Å with a
spectral resolution of ∼45000, and the GIRAFFE setups HR11
(5597-5840Å and R∼24000) and HR13 (6120-6405Å and R∼22000).
Objects:
-----------------------------------------------
RA (ICRS) DE Designation(s)
-----------------------------------------------
17 31 54.99 -67 02 54.0 NGC 6362 = GCl 66
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File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 87 160 Coordinates, magnitudes, atmospheric parameters,
[Fe/H] and [Na/Fe] abundance ratios for the
target member stars
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See also:
VII/202 : Globular Clusters in the Milky Way (Harris, 1997)
J/MNRAS/431/1995 : Deep uVI photometry of NGC2419 (Beccari+, 2013)
J/A+A/549/A41 : Horizontal branch stars in 47 Tuc and M5 (Gratton+, 2013)
J/A+A/548/A122 : Berkeley 39 stars photometry & abundances (Bragaglia+, 2012)
J/A+A/539/A19 : Horizontal branch stars in NGC 1851 (Gratton+, 2012)
J/AcA/62/357 : Proper motions in 6 globular clusters (Zloczewski+, 2012)
J/A+A/534/A123 : Horizontal branch stars in NGC 2808 (Gratton+, 2011)
J/A+A/534/A9 : Synthetic spectra of galactic GCs (Sbordone+, 2011)
J/MNRAS/412/81 : Lithium abundance in M4 red giants (Mucciarelli+, 2011)
J/A+A/524/A44 : CN and CH line strengths in 12 globulars (Pancino+, 2010)
J/MNRAS/405/839 : Spectroscopic obs. of globular clusters (Sharina+, 2010)
J/ApJ/695/L134 : Chemical anomalies in old LMC clusters (Mucciarelli+, 2009)
J/A+A/490/625 : Abundances of NGC 6121 red giants (Marino+, 2008)
J/AJ/130/2140 : Abundances & velocities in globular clusters (Pritzl+, 2005)
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 6 I6 --- ID [201343/802409] Stellar identifier from
Paper I (Dalessandro+, 2014ApJ...791L...4D 2014ApJ...791L...4D)
8- 18 F11.7 deg RAdeg Right Ascension in decimal degrees (J2000)
20- 30 F11.7 deg DEdeg Declination in decimal degrees (J2000)
32- 37 F6.3 mag Umag [16.5/18.1]?=0 The U band magnitude
39- 44 F6.3 mag Bmag [14.4/17.1] The B band magnitude
46- 51 F6.3 mag Vmag [12.9/16.2] The V band magnitude
53- 56 I4 K Teff [3886/6006] Effective temperature
58- 61 F4.2 [cm/s2] log(g) [0.6/2.7] Log surface gravity
63- 65 F3.1 km/s Vt [1.2/1.9] Turbulent velocity
67- 71 F5.2 [Sun] [Fe/H] [-1.3/-0.9] Log Fe/H abundance ratio
relative to Sun
73- 76 F4.2 [Sun] e_[Fe/H] [0.02/0.2] Uncertainty in [Fe/H]
78- 82 F5.2 [Sun] [Na/Fe] [-0.2/0.6] Log Na/Fe abundance ratio
relative to Sun
84- 87 F4.2 [Sun] e_[Na/Fe] [0.06/0.2] Uncertainty in [Na/Fe]
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History:
From electronic version of the journal
References:
Dalessandro et al. Paper I. 2014ApJ...791L...4D 2014ApJ...791L...4D
(End) Prepared by [AAS], Emmanuelle Perret [CDS] 16-Aug-2016