J/A+A/606/A94 Chemical abundances of 1059 FGK stars (Delgado Mena+, 2017)
Chemical abundances of 1111 FGK stars from the HARPS GTO planet search program.
II: Cu, Zn, Sr, Y, Zr, Ba, Ce, Nd, and Eu.
Delgado Mena E., Tsantaki M., Adibekyan V.Zh., Sousa S.G., Santos N.C.,
Gonzalez Hernandez J.I., Israelian G.
<Astron. Astrophys. 606, A94 (2017)>
=2017A&A...606A..94D 2017A&A...606A..94D (SIMBAD/NED BibCode)
ADC_Keywords: Stars, nearby ; Stars, double and multiple ; Abundances, peculiar
Keywords: stars: abundances - stars: fundamental parameters -
Galaxy: evolution - Galaxy: disc - solar neighborhood
Abstract:
To understand the formation and evolution of the different stellar
populations within our Galaxy it is essential to combine detailed
kinematical and chemical information for large samples of stars. The
aim of this work is to explore the chemical abundances of neutron
capture elements which are a product of different nucleosynthesis
processes taking place in diverse objects in the Galaxy, such as
massive stars, asymptotic giant branch (AGB) stars and supernovae
(SNe) explosions.
We derive chemical abundances of Cu, Zn, Sr, Y, Zr, Ba, Ce, Nd, and Eu
for a large sample of more than 1000 FGK dwarf stars with
high-resolution (R∼115000) and high-quality spectra from the
HARPS-GTO program. The abundances are derived by a standard local
thermodynamic equilibrium (LTE) analysis using measured equivalent
widths (EWs) injected to the code MOOG and a grid of Kurucz ATLAS9
atmospheres. Results. We find that thick disc stars are chemically
disjunct for Zn and Eu and also show on average higher Zr but lower Ba
and Y than the thin disc stars. We also discovered that the previously
identified high-alpha metal-rich population is also enhanced in Cu,
Zn, Nd, and Eu with respect to the thin disc but presents lower Ba and
Y abundances on average, following the trend of thick disc stars
towards higher metallities and further supporting the different
chemical composition of this population. By making a qualitative
comparison of O (pure alpha), Mg, Eu (pure r-process), and s-process
elements we can distinguish between the contribution of the more
massive stars (SNe II for alpha and r-process elements) and the lower
mass stars (AGBs) whose contribution to the enrichment of the Galaxy
is delayed, due to their longer lifetimes. The ratio of heavy-s to
light-s elements of thin disc stars presents the expected behaviour
(increasing towards lower metallicities) and can be explained by a
major contribution of low-mass AGB stars for s-process production at
disc metallicities. However, the opposite trend found for thick disc
stars suggests that intermediate-mass AGB stars play an important role
in the enrichment of the gas from where these stars formed. Previous
works in the literature also point to a possible primary production of
light-s elements at low metallicities to explain this trend. Finally,
we also find an enhancement of light-s elements in the thin disc at
super-solar metallicities which could be caused by the contribution of
metal-rich AGB stars.
This work proves the utility of homogeneous and high-quality data of
modest sample sizes. We find some interesting trends that might help
to differentiate thin and thick disc population (such as [Zn/Fe] and
[Eu/Fe] ratios) and that can also provide useful constraints for
Galactic chemical evolution models of the different populations in the
Galaxy.
Description:
The baseline sample used in this work is formed by 1111 FGK stars
observed within the context of the HARPS GTO programs. It is a
combination of three HARPS subsamples hereafter called HARPS-1 (Mayor
et al., 2003Msngr.114...20M 2003Msngr.114...20M), HARPS-2 (Lo Curto et al., 2010, Cat.
J/A+A/512/A48), and HARPS-4 (Santos et al., 2011, Cat.
J/A+A/526/A112).
The individual spectra of each star were reduced using the HARPS
pipeline and then combined with IRAF after correcting for its radial
velocity shift. The final spectra have a resolution of R∼115000 and
high signal-to-noise ratios (55%of the spectra have a S/N higher than
200). The total sample is composed of 136 stars with planets and 975
stars without detected planets. Chemical abundances of these samples
for refractory elements with A<29 can be found in Adibekyan et al.
(2012, Cat. J/A+A/545/A32) together with oxygen (Bertran de Lis et
al., 2015, Cat. J/A+A/576/A89), carbon (Suarez-Andres et al., 2017,
Cat. J/A+A/599/A96), lithium (Delgado Mena et al., 2014, Cat.
J/A+A/562/A92; 2015, Cat. J/A+A/576/A69), and nitrogen abundances
(Suarez-Andres et al., 2016A&A...591A..69S 2016A&A...591A..69S, only for a small fraction
of stars).
File Summary:
--------------------------------------------------------------------------------
FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
table1.dat 76 1059 Stellar parameters
table3.dat 296 1059 Abundances, errors, number of lines, S/N and
Galactic population
--------------------------------------------------------------------------------
See also:
J/A+A/410/527 : Abundances in the Galactic disk (Bensby+, 2003)
J/A+A/418/551 : Galactic disk stars abund. & velocities (Mishenina+, 2004)
J/MNRAS/367/1329 : Elemental abundances for 176 stars (Reddy+, 2006)
J/A+A/497/563 : Chemical abundances of 451 stars (Neves+, 2009)
J/A+A/512/A48 : HD125612, HD215497, HIP5158 HARPS RV curves (Lo Curto+ 2010)
J/A+A/526/A112 : Radial velocities of HARPS metal-poor sample (Santos+, 2011)
J/A+A/562/A92 : Li abundance in solar analogues (Delgado Mena+, 2014)
J/A+A/576/A69 : Li abundances in F stars (Delgado Mena+, 2015)
J/A+A/576/A89 : O abundances from HARPS in F-G stars (Bertran de Lis+, 2015)
J/A+A/599/A96 : Chemical abundances of 1110 stars (Suarez-Andres+, 2017)
J/A+A/545/A32 : Chemical abundances of 1111 FGK stars (Adibekyan+, 2012)
Byte-by-byte Description of file: table1.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 10 A10 --- Star Star's identifier
12- 15 I4 K Teff Effective temperature
17- 21 F5.1 K e_Teff Error of effective temperature
24- 27 F4.2 [cm/s2] logg Spectroscopic surface gravity
30- 33 F4.2 [cm/s2] e_logg Error of spectroscopic surface gravity
36- 39 F4.2 [cm/s2] loggHIP ?=9.99 Hipparcos Surface gravity
42- 45 F4.2 [cm/s2] e_loggHIP ?=9.99 Error of Hipparcos surface gravity
48- 52 F5.2 --- [Fe/H] Iron abundance
55- 58 F4.2 --- e_[Fe/H] Error of Iron abundance
61- 64 F4.2 km/s vtur Microturbulence velocity
67- 70 F4.2 km/s e_vtur Error of microturbulence velocity
73- 76 F4.2 [cm/s2] loggcor Corrected surface gravity
--------------------------------------------------------------------------------
Byte-by-byte Description of file: table3.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 10 A10 --- Star Star's identifier
14- 17 I4 --- S/N Signal to noise ratio
20- 24 A5 --- pop Galactic population
27- 31 F5.2 [Sun] [CuI/Fe] ?=9.99 Abundance [CuI/Fe] (Z=29)
35- 38 F4.2 [Sun] e_[CuI/Fe] ?=9.99 Error of [CuI/Fe]
41 I1 --- o_[CuI/Fe] [0/4] Number of CuI lines used
44- 48 F5.2 [Sun] [ZnI/Fe] Abundance [ZnI/Fe] (Z=30)
52- 55 F4.2 [Sun] e_[ZnI/Fe] Error of [ZnI/Fe]
58 I1 --- o_[ZnI/Fe] [1/3] Number of ZnI lines used
61- 65 F5.2 [Sun] [SrI/Fe] Abundance [SrI/Fe] (Z=38)
69- 72 F4.2 [Sun] e_[SrI/Fe] Error of [SrI/Fe]
75 I1 --- o_[SrI/Fe] [1] Number of SrI lines used
78- 82 F5.2 [Sun] [YII/Fe] Abundance [YII/Fe] (Z=39)
86- 89 F4.2 [Sun] e_[YII/Fe] Error of [YII/Fe]
92 I1 --- o_[YII/Fe] [4/6] Number of YII lines used
95- 99 F5.2 [Sun] [ZrI/Fe] ?=9.99 Abundance [ZrI/Fe] (Z=40)
103-106 F4.2 [Sun] e_[ZrI/Fe] ?=9.99 Error of [ZrI/Fe]
109 I1 --- o_[ZrI/Fe] [0/3] Number of ZrI lines used
112-116 F5.2 [Sun] [ZrII/Fe] ?=9.99 Abundance [ZrII/Fe] (Z=40)
120-123 F4.2 [Sun] e_[ZrII/Fe] ?=9.99 Error of [ZrII/Fe]
126 I1 --- o_[ZrII/Fe] [0/4] Number of ZrII lines used
129-133 F5.2 [Sun] [BaII/Fe] Abundance [BaII/Fe] (Z=56)
137-140 F4.2 [Sun] e_[BaII/Fe] Error of [BaII/Fe]
143 I1 --- o_[BaII/Fe] [2/3] Number of BaII lines used
146-150 F5.2 [Sun] [CeII/Fe] ?=9.99 Abundance [CeII/Fe] (Z=58)
154-157 F4.2 [Sun] e_[CeII/Fe] ?=9.99 Error of [CeII/Fe]
160 I1 --- o_[CeII/Fe] [0/4] Number of CeII lines used
163-167 F5.2 [Sun] [NdII/Fe] ?=9.99 Abundance [NdII/Fe] (Z=60)
171-174 F4.2 [Sun] e_[NdII/Fe] ?=9.99 Error of [NdII/Fe]
177 I1 --- o_[NdII/Fe] [0/4] Number of NdII lines used
180-184 F5.2 [Sun] [EuII/Fe] ?=9.99 Abundance [EuII/Fe] (Z=63)
188-191 F4.2 [Sun] e_[EuII/Fe] ?=9.99 Error of [EuII/Fe]
194 I1 --- o_[EuII/Fe] [0/1] Number of EuII lines used
197-201 F5.2 [Sun] [AlI/Fe] ?=9.99 Abundance [AlI/Fe] (Z=63)
205-208 F4.2 [Sun] e_[AlI/Fe] ?=9.99 Error of [AlI/Fe]
211 I1 --- o_[AlI/Fe] [0/2] Number of AlI lines used
214-218 F5.2 [Sun] [MgI/Fe] Abundance [MgI/Fe] (Z=63)
222-225 F4.2 [Sun] e_[MgI/Fe] Error of [MgI/Fe]
228 I1 --- o_[MgI/Fe] [2/3] Number of MgI lines used
231-235 F5.2 [Sun] [SiI/Fe] Abundance [SiI/Fe] (Z=63)
239-242 F4.2 [Sun] e_[SiI/Fe] Error of [SiI/Fe]
244-245 I2 --- o_[SiI/Fe] [4/14] Number of SiI lines used
248-252 F5.2 [Sun] [CaI/Fe] Abundance [CaI/Fe] (Z=63)
256-259 F4.2 [Sun] e_[CaI/Fe] Error of [CaI/Fe]
261-262 I2 --- o_[CaI/Fe] [7/12] Number of CaI lines used
265-269 F5.2 [Sun] [TiI/Fe] Abundance [TiI/Fe] (Z=63)
273-276 F4.2 [Sun] e_[TiI/Fe] Error of [TiI/Fe]
278-279 I2 --- o_[TiI/Fe] [8/22] Number of TiI lines used
282-286 F5.2 [Sun] [TiII/Fe] Abundance [TiII/Fe] (Z=63)
290-293 F4.2 [Sun] e_[TiII/Fe] Error of [TiII/Fe]
296 I1 --- o_[TiII/Fe] [4/5] Number of TiII lines used
--------------------------------------------------------------------------------
Acknowledgements:
Elisa Delgado Mena, elisa.delgado(at)astro.up.pt
References:
Adibekyan et al., Paper I 2012A&A...545A..32A 2012A&A...545A..32A, Cat. J/A+A/545/A32
(End) Elisa Delgado Mena [IA, Portugal], Patricia Vannier [CDS] 12-Jul-2017