J/ApJ/716/L166 Lithium abundances in red giants of M4 (D'Orazi+, 2010)
Lithium abundances in red giants of M4: evidence for asymptotic giant branch
star pollution in globular clusters?
D'Orazi V., Marino A.F.
<Astrophys. J., 716, L166-L169 (2010)>
=2010ApJ...716L.166D 2010ApJ...716L.166D
ADC_Keywords: Clusters, globular ; Abundances ; Stars, giant
Keywords: globular clusters: individual (NGC 6121) - stars: abundances -
stars: individual (Population II)
Abstract:
The determination of Li and proton-capture element abundances in
globular cluster (GC) giants allows us to constrain several key
questions on the multiple population scenarios in GCs, from formation
and early evolution to pollution and dilution mechanisms. In this
Letter, we present our results on Li abundances for a large sample of
giants in the intermediate-metallicity GC NGC 6121 (M4), for which Na
and O have been already determined by Marino et al. (2008, Cat.
J/A+A/490/625). The stars analyzed are both below and above the red
giant branch bump luminosity. We found that the first and second
generation stars share the same Li content, suggesting that a Li
production must have occurred. This provides strong observational
evidence supporting the scenario in which asymptotic giant branch
stars are GC polluters.
Description:
Our sample consists of 104 RGB stars, whose spectra were acquired with
FLAMES on VLT/UT2 with the fiber link to the high-resolution
spectrograph UVES (R∼40000). A detailed description of observations,
target properties, and data reduction and derivation of atmospheric
parameters is provided in Marino et al. (2008, Cat. J/A+A/490/625).
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 44 104 Stellar parameters and abundances for our sample
stars
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See also:
J/A+A/539/A157 : Lithium and sodium in M4 (Monaco+, 2012)
J/MNRAS/412/81 : Lithium abundance in M4 red giants (Mucciarelli+, 2011)
J/A+A/490/625 : Abundances of NGC 6121 red giants (Marino+, 2008)
J/ApJ/689/1031 : Heavy element abundances in giant stars (Yong+, 2008)
J/AJ/127/2771 : HST proper-motions of M4 main-sequence stars (Richer+, 2004)
J/AJ/124/1486 : M4 UBV color-magnitude diagrams (Mochejska+, 2002)
J/ApJS/120/265 : HST photometry of M4 (Ibata+, 1999)
J/AJ/114/189 : M 4 CCD photometry (Alcaino+, 1997)
J/PAZh/22/847 : Identification and coordinates in M4 (Shokin+, 1996)
J/ApJ/443/124 : Radial Velocities of Stars in M4 (Peterson+ 1995)
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 5 I5 --- Star [5359/45895] Stellar identification number
(<Cl* NGC 6121 MVP NNNNN> in Simbad)
7- 10 I4 K Teff [3860/4950] Effective temperature
12- 15 F4.2 [cm/s2] log(g) [0.5/3.05] Log of the surface gravity
17- 20 F4.2 km/s xi [1.1/1.88] Turbulent velocity
22- 26 F5.2 [-] [Na/Fe] [-0.05/0.53] Log Na/Fe number abundance ratio
29- 32 F4.2 [-] e_[Na/Fe] Error in [Na/Fe]
35- 38 F4.2 [-] logn(Li) [0/1.62] Log of Li number abundance
41- 44 F4.2 [-] e_logn(Li) Error in logn(Li)
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History:
From electronic version of the journal
(End) Greg Schwarz [AAS], Emmanuelle Perret [CDS] 04-Jun-2012