J/A+A/634/A136 Chemical sulfur abundances of 719 FGK stars (Costa Silva+, 2020)
Chemical abundances of 1111 FGK stars from the HARPS GTO planet search program.
III: Sulfur.
Costa Silva A.R., Delgado Mena E., Tsantaki M.
<Astron. Astrophys. 634, A136 (2020)>
=2020A&A...634A.136C 2020A&A...634A.136C (SIMBAD/NED BibCode)
ADC_Keywords: Stars, nearby ; Stars, double and multiple ; Abundances, peculiar
Keywords: astrochemistry - stars: abundances - Galaxy: disk -
solar neighbourhood
Abstract:
Elemental abundances are of prime importance to help us
reconstruct the origin and evolution of stars and galaxies in our
Universe. Sulfur abundances have not been as heavily studied as other
elements, so some details regarding its behaviour are still unclear.
We aim to investigate [S/Fe] ratios in stars of the solar
neighbourhood in order to analyse the chemical evolution of sulfur and
probe for possible differences in abundances of planet host and
non-planet host stars.
We use the code MOOG to perform spectral synthesis and derive v*sin(i)
values and [S/Fe] ratios for 719 FGK stars with high-resolution
(R∼115000) and high-quality spectra from the HARPS-GTO program. We
find the best fit and corresponding parameter values by performing
chi-square minimisation of the deviation between synthetic profiles
and observational spectra.
Our results reveal that sulfur behaves as a typical alpha-element,
with low abundances in young thin disk stars and high abundances in
old thick disk stars, following what was expected from our
understanding of the Galactic chemical evolution (GCE). Nevertheless,
further studies into the abundances of sulfur in very metal-poor stars
are required as our sample only derived sulfur abundances to stars
with metallicity as low as [Fe/H]=-1.13dex. High-alpha metal rich
stars are more enhanced in sulfur compared to their thin disk
counterparts at the same metallicity. We compare our results to GCE
models from other authors in the [S/Fe] vs. [Fe/H] plane. The
[S/Fe]-age relationship is a good proxy for time, just like it is the
case with other alpha-elements. We report no differences in the
abundances of sulfur between stars with and without planetary
companions in the metallicity range [Fe/H]≥-0.3dex.
Description:
Spectral synthesis on a sample of 1059 HARPS-GTO solar neighbourhood
stars was performed, for lines of Multiplet 8 (triplets at 6743Å
and 6757Å), [S/Fe] ratios for 719 of the stars and for the Sun have
been obtained, through a Vesta-reflected spectrum.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table3.dat 92 719 Stellar parameters, abundances of sulfur, errors,
number of lines, planet companions, S/N and
Galactic population
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See also:
J/A+A/545/A32 : Chemical abundances of 1111 FGK stars (Adibekyan+, 2012)
J/A+A/606/A94 : Chemical abundances of 1059 FGK stars (Delgado Mena+, 2017)
Byte-by-byte Description of file: table3.dat
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Bytes Format Units Label Explanations
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1- 10 A10 --- Star Star's identifier
12- 17 F6.1 K Teff Effective temperature
19- 22 F4.2 [cm/s2] logg Spectroscopic surface gravity
24- 28 F5.2 --- [Fe/H] Iron abundance
30- 35 F6.3 Gyr Age ? Stellar age
37- 41 F5.3 Gyr e_Age ? Error of stellar age
43- 47 F5.3 km/s vsini Rotational velocity
49- 53 F5.3 km/s vmac Macroturbulence velocity
55- 60 F6.3 [Sun] [S/Fe] Abundance of [S/Fe] (Z=16)
62- 66 F5.3 [Sun] e_[S/Fe] Error of [S/Fe]
68- 73 A6 --- o_[S/Fe] Number of SI lines used (when only one,
indicates which one)
75- 78 A4 --- Planet Planet companion (jup, nept or none)
80- 84 A5 --- Pop Galactic population (1)
86- 92 F7.2 --- S/N Signal to noise ratio
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Note (1): Galactic population as follows:
thick = thick disk
thin = thin disk
halo = halo
hamr = high-alpha metal-rich, group of Galactic disc stars with
high metallicity ([Fe/H]>-0.2dex)
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Acknowledgements:
Ana Rita Costa Silva, ana.rita(at)astro.up.pt
References:
Adibekyan et al., Paper I 2012A&A...545A..32A 2012A&A...545A..32A, Cat. J/A+A/545/A32
Delgado Mena et al., Paper II 2017A&A...606A..94D 2017A&A...606A..94D, Cat. J/A+A/606/A94
(End) Ana Rita Costa Silva [IA, Portugal], Patricia Vannier [CDS] 30-Jan-2020