J/ApJ/731/64 Spectroscopy of 300 RGBs in ω Cen (Marino+, 2011)
Sodium-oxygen anticorrelation and neutron-capture elements in Omega Centauri
stellar populations.
Marino A.F., Milone A.P., Piotto G., Villanova S., Gratton R., D'Antona F.,
Anderson J., Bedin L.R., Bellini A., Cassisi S., Geisler D., Renzini A.,
Zoccali M.
<Astrophys. J., 731, 64 (2011)>
=2011ApJ...731...64M 2011ApJ...731...64M
ADC_Keywords: Abundances, [Fe/H] ; Stars, giant ; Clusters, globular
Keywords: globular clusters: individual (NGC 5139) - stars: abundances -
stars: Population II
Abstract:
Omega Centauri is no longer the only globular cluster known to contain
multiple stellar populations, yet it remains the most puzzling. Due to
the extreme way in which the multiple stellar population phenomenon
manifests in this cluster, it has been suggested that it may be the
remnant of a larger stellar system. In this work, we present a
spectroscopic investigation of the stellar populations hosted in the
globular cluster ω Centauri to shed light on its still puzzling
chemical enrichment history. With this aim, we used FLAMES+GIRAFFE@VLT
to observe 300 stars distributed along the multimodal red giant branch
of this cluster, sampling with good statistics the stellar populations
of different metallicities. We determined chemical abundances for Fe,
Na, O, and n-capture elements Ba and La. We confirm that ω
Centauri exhibits large star-to-star variations in iron with [Fe/H]
ranging from ~-2.0 to ~-0.7dex. Barium and lanthanum abundances of
metal-poor stars are correlated with iron, up to [Fe/H]~-1.5, while
they are almost constant (or at least have only a moderate increase)
in the more metal-rich populations. There is an extended Na-O
anticorrelation for stars with [Fe/H]≲-1.3 while more metal-rich
stars are almost all Na-rich. Sodium was found to mildly increase with
iron over the entire metallicity range.
Description:
The data set consists of a large number of FLAMES/GIRAFFE spectra
(proposals: 071.D-0217(A), 082.D-0424(A)) taken with the four setups
HR09B, HR11, HR13, and HR15, which cover a spectral coverage of
5095-5404, 5597-5840, 6120-6405, and 6607-6965Å, respectively, with
a resolution R∼20000-25000. The sample is composed of 300 red giants
with V≤15.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 81 300 Coordinates RA and DEC, V magnitude, adopted
atmospheric parameters and measured abundance
ratios for the 300 stars in ω Cen
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See also:
J/MNRAS/416/L6 : AGB and RGB stars in ω Cen (McDonald+, 2011)
J/ApJ/722/1373 : ω Centauri giants abundances (Johnson+, 2010)
J/ApJ/698/2048 : Abundances of red giants in ω Cen (Johnson+, 2009)
J/MNRAS/396/2183 : RVs of red giants in ω Cen (Sollima+ 2009)
J/ApJ/681/1505 : Abundances of red giants in ω Cen (Johnson+, 2008)
J/ApJ/661/L155 : Radial velocities RGB stars in omega Cen (Pancino+, 2007)
J/ApJ/647/1075 : Age-metallicity relation of ω Cen (Stanford+, 2006)
J/MNRAS/357/265 : BVI photometry of omega Cen red giants (Sollima+, 2005)
J/A+A/360/472 : Proper motions in omega Centauri (van Leeuwen+, 2000)
J/ApJ/462/241 : Ca abundance for Omega Cen red giants (Norris+ 1996)
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 7 A7 --- ID Identification from the photometric catalog of
Bellini et al. (2009A&A...507.1393B 2009A&A...507.1393B) (
or RGB.NNN formats)
9- 18 F10.6 deg RAdeg Right Ascension in decimal degrees (J2000)
20- 29 F10.6 deg DEdeg Declination in decimal degrees (J2000)
31- 36 F6.3 mag Vmag V band magnitude
38- 41 I4 K Teff Effective temperature
43- 46 F4.2 [cm/s2] log(g) Log of the surface gravity
48- 51 F4.2 km/s Vt Microturbulent velocity
53- 57 F5.2 [Sun] [Fe/H] Log of the Fe/H number abundance
59- 63 F5.2 [Sun] [O/Fe] ? Log of the O/Fe number abundance
65- 69 F5.2 [Sun] [Na/Fe] ? Log of the Na/Fe number abundance
71- 75 F5.2 [Sun] [Ba/Fe] Log of the Ba/Fe number abundance
77- 81 F5.2 [Sun] [La/Fe] ? Log of the La/Fe number abundance
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Nomenclature notes:
NNNNNN formats are <Cl* NGC 5139 WFI NNNNNN> in Simbad from
Pancino et al., 2007, Cat. J/ApJ/661/L155
else <[MMP2011] RGB NNN> in Simbad.
History:
From electronic version of the journal
(End) Greg Schwarz [AAS], Emmanuelle Perret [CDS] 18-Oct-2012