J/A+A/647/A162      AMBRE catalogue of sulfur abundances       (Perdigon+, 2021)
The AMBRE Project: Origin and evolution of sulfur in the Milky Way.
    Perdigon J., de Laverny P., Recio-Blanco A., Fernandez-Alvar E.,
    Santos-Peral P., Kordopatis G., Alvarez M.A.
    <Astron. Astrophys. 647, A162 (2021)>
    =2021A&A...647A.162P 2021A&A...647A.162P        (SIMBAD/NED BibCode)
ADC_Keywords: Stars, late-type ; Abundances, [Fe/H] ; Spectroscopy
Keywords: Galaxy: abundances - Galaxy: evolution - stars: abundances
Abstract:
    Sulfur is a volatile chemical element that plays an important role in
    tracing the chemical evolution of the Milky Way and external galaxies.
    However, its nucleosynthesis origin and abundance variations in the
    Galaxy are still unclear because the number of available stellar
    sulfur abundance measurements is currently rather small.
    The goal of the present article is to accurately and precisely study
    the sulfur content of large number of stars located in the solar
    neighbourhood. We use the parametrisation of thousands of
    high-resolution stellar spectra provided by the AMBRE Project, and
    combine it with the automated abundance determination GAUGUIN to
    derive local thermodynamic equilibrium (LTE) sulfur abundances for
    1855 slow-rotating FGK-type stars.
    This is the largest and most precise catalogue of sulfur abundances
    published to date. It covers a metallicity domain as high as ∼2.5dex
    starting at [M/H]≲-2.0dex.
    We find that the sulfur-to-iron abundances ratio is compatible with a
    plateau-like distribution in the metal-poor regime, and then starts to
    decrease continuously at [M/H]~-1.0dex. This decrease continues
    towards negative values for supersolar metallicity stars as recently
    reported for magnesium and as predicted by Galactic chemical evolution
    models. Moreover, sulfur-rich stars having metallicities in the range
    [-1.0,-0.5] have very different kinematical and orbital properties
    with respect to more metal-rich and sulfur-poor ones. Two disc
    components, associated with the thin and thick discs, are thus seen
    independently in kinematics and sulfur abundances. The sulfur radial
    gradients in the Galactic discs have also been estimated. Finally, the
    enrichment in sulfur with respect to iron is nicely correlated with
    stellar ages: older metal-poor stars have higher [S/M] ratios than
    younger metal-rich ones.
    This work has confirmed that sulfur is an α-element that could
    be considered to explore the Galactic populations properties. For the
    first time, a chemo-dynamical study from the sulfur abundance point of
    view, as a stand-alone chemical element, is performed.
Description:
    We present LTE sulfur abundances derived from the three main
    components of the multiplet 8 system lines found around 675nm, which
    are known to be poorly affected by NLTE effects. This study analysed
    100,000 spectra (including several repeats per stars) retrieved from
    the ESO archives of the HARPS, FEROS, and UVES instruments. These
    sulfur abundances have been homogeneously measured at a spectral
    resolution of 40,000 thanks to (i) stellar atmospheric parameters
    previously determined within the AMBRE Project (de Laverny et al.,
    2013, The Messenger, 153, 18); (ii) GAUGUIN, an optimisation method
    based on the Gauss-Newton algorithm; and (iii) a precomputed grid of
    synthetic spectra with [S/H] abundances varying from -3.0 to +2.0dex.
File Summary:
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 FileName      Lrecl  Records   Explanations
--------------------------------------------------------------------------------
ReadMe            80        .   This file
table5.dat        86     1855   AMBRE catalogue of LTE sulfur abundances
table6.dat       111       13   AMBRE LTE sulfur abundances of the Gaia
                                 benchmarks stars adopting their recommended
                                 atmospheric parameters
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See also:
 J/A+A/542/A48  : AMBRE project. FEROS archived spectra (Worley+, 2012)
 J/A+A/595/A18  : Lithium abundances in AMBRE stars (Guiglion+, 2016)
 J/A+A/600/A22  : Iron-peak elements in solar neighbourhood (Mikolaitis+, 2017)
 J/A+A/619/A130 : Solar sibling candidates chemical abundances (Adibekyan+,2018)
 J/A+A/619/A143 : r-process abundances in AMBRE stars (Guiglion+, 2018)
Byte-by-byte Description of file: table5.dat
--------------------------------------------------------------------------------
  Bytes Format Units   Label      Explanations
--------------------------------------------------------------------------------
  1- 19  I19   ---     GaiaDR2    ? Gaia DR2 ID
 21- 28  A8    ---     Name       HD name for six very bright stars not present
                                   in the Gaia second data release
 31- 35  F5.1  ---     S/N        Signal-to-noise ratio
 37- 42  F6.1  K       Teff       Effective temperature
 44- 48  F5.2  [cm/s2] logg       Surface gravity (log scale)
 50- 54  F5.2  [-]     [M/H]      Mean stellar metallicity
 56- 60  E5.2  [-]     [alpha/Fe] Ratio between alpha-elements and Fe abundances
 62- 65  I4    ---     N6743      Number of S-6743 analysed
 67- 70  I4    ---     N6748      Number of S-6748 analysed
 72- 75  I4    ---     N6757      Number of S-6757 analysed
 77- 81  F5.2  [-]     [S/H]      LTE sulfur abundance
 83- 86  F4.2  [-]   s_[S/H]      ? Dispersion associated to [S/H]
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Byte-by-byte Description of file: table6.dat
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   Bytes Format Units  Label      Explanations
--------------------------------------------------------------------------------
   1- 11  A11   ---    Star       Star Name
  13- 20  A8    ---    HD         HD name
  22- 40  I19   ---    GaiaDR2    ? Gaia DR2 ID
      42  A1    ---  l_S/N        Limit flag on S/N
  43- 46  I4    ---    S/N        Signal-to-noise ratio
  48- 51  I4    K      Teff       Effective temperature
  53- 56  F4.2  [cm/s] logg       Surface gravity (log scale)
  58- 62  F5.2  [-]    [M/H]      Mean stellar metallicity
  64- 68  F5.2  [-]    [alpha/Fe] Ratio between alpha-elements and Fe abundances
  70- 73  I4    ---    N6743      Number of S-6743 analysed
  75- 78  I4    ---    N6748      Number of S-6748 analysed
  80- 83  I4    ---    N6757      Number of S-6757 analysed
  85- 89  F5.2  [-]    [S/H]      LTE sulfur abundance
  91- 94  F4.2  [-]  s_[S/H]      ? Dispersion associated to [S/H]
  96-111  A16   ---    Type       Type of stars
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Acknowledgements:
    Patrick de Laverny, laverny(at)oca.eu
(End) Patrick de Laverny [Obs. Cote d'Azur], Patricia Vannier [CDS]  12-Feb-2021