J/AJ/152/21 Abundances for red giants in NGC 6342 and NGC 6366 (Johnson+, 2016)
The chemical composition of red giant branch stars in the galactic globular
clusters NGC 6342 and NGC 6366.
Johnson C.I., Caldwell N., Rich R.M., Pilachowski C.A., Hsyu T.
<Astron. J., 152, 21-21 (2016)>
=2016AJ....152...21J 2016AJ....152...21J (SIMBAD/NED BibCode)
ADC_Keywords: Milky Way ; Clusters, globular ; Stars, giant ; Stars, nearby ;
Radial velocities ; Abundances ; Effective temperatures
Keywords: globular clusters: general - stars: abundances -
globular clusters: individual (NGC 6342, NGC 6366)
Abstract:
We present radial velocities and chemical abundances for red giant
branch stars in the Galactic bulge globular clusters NGC6342 and
NGC6366. The velocities and abundances are based on measurements of
high-resolution (R≳20000) spectra obtained with the MMT-Hectochelle
and WIYN-Hydra spectrographs. We find that NGC6342 has a heliocentric
radial velocity of +112.5km/s (σ=8.6km/s), NGC6366 has a
heliocentric radial velocity of -122.3km/s (σ=1.5km/s), and both
clusters have nearly identical metallicities ([Fe/H]~-0.55). NGC6366
shows evidence of a moderately extended O-Na anti-correlation, but
more data are needed for NGC6342 to determine if this cluster also
exhibits the typical O-Na relation likely found in all other Galactic
globular clusters. The two clusters are distinguished from similar
metallicity field stars as having larger [Na/Fe] spreads and enhanced
[La/Fe] ratios, but we find that NGC6342 and NGC6366 display α
and Fe-peak element abundance patterns that are typical of other
metal-rich ([Fe/H]>-1) inner Galaxy clusters. However, the median
[La/Fe] abundance may vary from cluster-to-cluster.
Description:
The spectra for this project were obtained using the Hectochelle and
Hydra multi-fiber bench spectrographs mounted on the MMT 6.5m and WIYN
3.5m telescopes, respectively. NGC6342 was observed with Hectochelle
on 2014 June 18 and also with Hydra on 2013 June 27. However, NGC6366
was only observed with Hydra on 2012 May 18. The Hectochelle
observations consisted of a 2400 and 2065s exposure set using the 110
line/mm Echelle grating, the "CJ26" filter, and 2*1
(spatial*dispersion) binning to achieve a resolving power of
R=λ/Δλ∼38000. Similarly, the Hydra observations
consisted of 3*3600s exposures with the bench configured to use the
316line/mm Echelle grating, the X18 filter, the red camera and fibers,
and 2*1 binning to achieve a resolving power of R∼18000. The spectra
spanned approximately 6140-6310Å for the Hectochelle data and
6080-6390Å for the Hydra data.
The target stars for both clusters were selected using photometry and
coordinates available through the Two Micron All Sky Survey (2MASS;
Cutri et al. 2003, Cat. II/246).
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 76 267 NGC 6342 coordinates, photometry, and velocities
table2.dat 76 51 NGC 6366 coordinates, photometry, and velocities
table3.dat 90 17 NGC 6342 and NGC 6366 stellar atmosphere
parameters and abundance ratios
table4.dat 53 52 Line list and adopted reference abundances
table5.dat 66 17 NGC 6342 and NGC 6366 abundance ratio uncertainties
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See also:
II/246 : 2MASS All-Sky Catalog of Point Sources (Cutri+ 2003)
VII/202 : Globular Clusters in the Milky Way (Harris, 1997)
J/A+A/584/A59 : Proper motions and membership in NGC 6366 (Sariya+, 2015)
J/ApJ/810/148 : Red giant abundances in NGC 2808 (Carretta, 2015)
J/AJ/148/67 : Abundances of 156 bulge red giants (Johnson+, 2014)
J/A+A/549/A147 : Abundances of microlensed Bulge dwarf stars (Bensby+, 2013)
J/ApJ/765/157 : Abundances of red giants in the Gal. bulge (Johnson+, 2013)
J/A+A/540/A27 : Spectroscopy in Galactic globular clusters (Saviane+, 2012)
J/ApJ/749/175 : Abundances for stars in Plaut's window (Johnson+, 2012)
J/ApJ/732/108 : Abundances of 92 giants in Plaut's window (Johnson+, 2011)
J/A+A/534/A80 : [Fe/H] of bulge clump giants in Baade's window (Hill+, 2011)
J/A+A/533/A134 : Abundances of microlensed stars in the Bulge (Bensby+, 2011)
J/A+A/530/A54 : Abundances of 650 bulge red giants (Gonzalez+, 2011)
J/A+A/513/A35 : Abundances of Galactic red giants (Alves-Brito+, 2010)
J/A+A/505/139 : Abundances of red giants in 17 GCs (Carretta+, 2009)
J/A+A/505/117 : Abundances of red giants in 15 GCs (Carretta+, 2009)
J/other/RMxAA/44.365 : New variable stars in NGC 6366 (Arellano Ferro+, 2008)
J/A+A/464/967 : Abundances of red giants in NGC 6388 (Carretta+, 2007)
J/A+A/464/953 : Abundances of red giants in NGC 6441 (Gratton+, 2007)
J/A+A/455/271 : Abundances of red giants in NGC 6441 (Gratton+, 2006)
J/A+A/450/105 : Properties of 153 Galactic globular clusters (Bica+, 2006)
J/MNRAS/351/1204 : IR Photometry of 10 Galactic GCs (Valenti+, 2004)
J/ApJ/590/797 : Parameters of galactic GCs (Van Den Bregh+, 2003)
J/AJ/106/604 : Study of globular cluster NGC 6366 (Harris 1993)
Byte-by-byte Description of file: table[12].dat
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Bytes Format Units Label Explanations
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1 A1 --- Mm Membership type description (a, b, c, or d) (1)
3- 18 A16 --- 2MASS 2MASS identifier (HHMMSSss-DDMMSSs, J2000)
20 A1 --- f_2MASS [h] Flag on 2MASS (h=star observed with both
Hectochelle and Hydra instruments)
22- 31 F10.6 deg RAdeg Right Ascension in decimal degrees (J2000)
33- 42 F10.6 deg DEdeg Declination in decimal degrees (J2000)
44- 49 F6.3 mag Jmag [9.3/13.9] 2MASS J band magnitude
51- 56 F6.3 mag Hmag [8.3/13.3] 2MASS H band magnitude
58- 63 F6.3 mag Ksmag [8/12.9] 2MASS Ks band magnitude
65- 71 F7.2 km/s HRV [-222.3/278.6] Heliocentric radial velocity
73- 76 F4.2 km/s e_HRV [0.1/4.1] Error in HRV
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Note (1): The codes for the type description are defined as below:
a = Hectochelle probable members;
b = Hectochelle probable non-members
c = Hydra probable members;
d = Hydra probable non-members;
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Byte-by-byte Description of file: table3.dat
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Bytes Format Units Label Explanations
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1- 4 I4 --- NGC [6342/6366] Cluster NGC number (6342 or 6366)
6- 21 A16 --- 2MASS 2MASS identifier (HHMMSSss-DDMMSSs, J2000)
23- 26 I4 --- Teff [4175/4850] Effective temperature
28- 31 F4.2 [cm/s2] logg [1.4/2.75] Log surface gravity (in cgs unit)
33- 37 F5.2 [Sun] [Fe/H] [-0.67/-0.41] Metallicity
39- 42 F4.2 km/s Vt [1.55/2.2] Microturbulence ({dzeta}mic.)
44- 48 F5.2 [Sun] [O/Fe] [0.27/0.77]? The [O/Fe] abundance ratio
50- 54 F5.2 [Sun] [Na/Fe] [-0.16/0.46] The [Na/Fe] abundance ratio
56- 60 F5.2 [Sun] [Mg/Fe] [0.14/0.41]? The [Mg/Fe] abundance ratio
62- 66 F5.2 [Sun] [Si/Fe] [0.18/0.49] The [Si/Fe] abundance ratio
68- 72 F5.2 [Sun] [Ca/Fe] [0.15/0.48]? The [Ca/Fe] abundance ratio
74- 78 F5.2 [Sun] [Cr/Fe] [-0.24/0.17]? The [Cr/Fe] abundance ratio
80- 84 F5.2 [Sun] [Ni/Fe] [-0.04/0.18]? The [Ni/Fe] abundance ratio
86- 90 F5.2 [Sun] [La/Fe] [-0.05/0.33]? The [La/Fe] abundance ratio
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Byte-by-byte Description of file: table4.dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 5 A5 --- Species Element and degree of ionization
7- 13 A7 --- Col Name of the column in Table 3 giving the ion
abundance (added at CDS)
15- 21 F7.2 0.1nm lambda [6094.3/6336.9] Wavelength λ
23- 26 F4.2 eV EP [0/5.9] Excitation potential
28- 30 A3 --- f_loggf [hfs] Flag on loggf (hfs=abundance calculated
by taking hyperfine structure into account) (1)
32- 37 F6.3 [-] loggf [-9.8/-0.2]? Log oscillator strength log(gf)
39- 42 F4.2 [-] logEsun [1.1/8.7] Log Solar reference abundance
(logε(X)☉)
44- 47 F4.2 [-] logEarc [0.5/8.7] Log Arcturus reference abundance
(logε(X)Arc.)
49- 53 F5.2 [Sun] Abund [-0.5/0.5] Abundance [X/Fe] or [Fe/H]Arc.
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Note (1): See Section 3.2 for details about the hyperfine structure.
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Byte-by-byte Description of file: table5.dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 4 I4 --- NGC [6342/6366] Cluster NGC number (6342 or 6366)
6- 21 A16 --- 2MASS 2MASS identifier (HHMMSSss-DDMMSSs, J2000)
23- 26 F4.2 [Sun] dFe [0.04/0.07] Error of the mean for [Fe/H]
(Δ[Fe/H])
28- 31 F4.2 [Sun] dO [0.08/0.1]? Error of the mean for [O/Fe]
(Δ[O/H])
33- 36 F4.2 [Sun] dNa [0.06/0.1] Error of the mean for [Na/Fe]
(Δ[Na/H])
38- 41 F4.2 [Sun] dMg [0.05/0.11]? Error of the mean for [Mg/Fe]
(Δ[Mg/H])
43- 46 F4.2 [Sun] dSi [0.07/0.12] Error of the mean for [Si/Fe]
(Δ[Si/H])
48- 51 F4.2 [Sun] dCa [0.09/0.13]? Error of the mean for [Ca/Fe]
(Δ[Ca/H])
53- 56 F4.2 [Sun] dCr [0.11/0.13]? Error of the mean for [Cr/Fe]
(Δ[Cr/H])
58- 61 F4.2 [Sun] dNi [0.07/0.13]? Error of the mean for [Ni/Fe]
(Δ[Ni/H])
63- 66 F4.2 [Sun] dLa [0.08/0.1] Error of the mean for [La/Fe]
(Δ[La/H])
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History:
From electronic version of the journal
(End) Prepared by [AAS]; Sylvain Guehenneux [CDS] 21-Sep-2016