J/MNRAS/516/3786 Gd, Dy, and Th abundances in MW-disc stars (Mishenina+, 2022)
Enrichment of the Galactic disc with neutron-capture elements Gd, Dy, and Th.
Mishenina T., Pignatari M., Gorbaneva T., Cote B., Yague Lopez A.,
Thielemann F.-K., Soubiran C.
<Mon. Not. R. Astron. Soc. 516, 3786-3801 (2022)>
=2022MNRAS.516.3786M 2022MNRAS.516.3786M (SIMBAD/NED BibCode)
ADC_Keywords: Galactic plane ; Milky Way ; Stars, late-type ; Spectroscopy ;
Optical ; Abundances, [Fe/H] ; Abundances, peculiar ;
Effective temperatures ; Velocity dispersion
Keywords: stars: abundances - stars: late-type - Galaxy: disc -
Galaxy: evolution
Abstract:
The study of the origin of heavy elements is one of the main goals of
nuclear astrophysics. In this paper, we present new observational data
for the heavy r-process elements gadolinium (Gd, Z= 64), dysprosium
(Dy, Z= 66), and thorium (Th, Z= 90) in a sample of 276 Galactic disc
stars (-1.0 < [Fe/H] < + 0.3). The stellar spectra have a high
resolution of 42000 and 75000, and the signal-to- noise ratio higher
than 100. The LTE abundances of Gd, Dy, and Th have been determined by
comparing the observed and synthetic spectra for three Gd lines (149
stars), four Dy lines (152 stars), and the Th line at 4019.13 Å
(170 stars). For about 70 per cent of the stars in our sample, Gd and
Dy are measured for the first time, and Th for 95 per cent of the
stars. Typical errors vary from 0.07 to 0.16 dex. This paper provides
the first extended set of Th observations in the Milky Way disc.
Together with europium (Eu, Z= 63) data from our previous studies, we
have compared these new observations with nucleosynthesis predictions
and Galactic Chemical Evolution simulations. We confirm that [Gd/Fe]
and [Dy/Fe] show the same behaviour of Eu. We study with GCE
simulations the evolution of [Th/Fe] in comparison with [Eu/Fe],
showing that unlike Eu, either the Th production is metallicity
dependent in case of a unique source of the r-process in the Galaxy,
or the frequency of the Th-rich r-process source is decreasing with
the increase in [Fe/H].
Description:
This study was carried out on an initial list of 276 stars and based
on the spectra and atmospheric parameters by Mishenina et al.
(2013A&A...552A.128M 2013A&A...552A.128M, Cat. J/A+A/552/A128). Data were acquired with
1.93-m telescope at the OHP and the echelle-type spectrograph ELODIE
were employed to obtain spectra at the resolving power R = 42000 in
the wavelength range from 4400 to 6800 Å and with the S/N better
than 100 at 5500 Å. We also used additional spectra from the OHP
spectroscopic archive (Moultaka et al. 2004PASP..116..693M 2004PASP..116..693M,
http://atlas.obs-hp.fr/elodie/) collected with the SOPHIE spectrograph
and covering a similar wavelength range at the spectral resolution R =
75000 (i.e see section 2 for spectrum data processing and description
of (Teff, logg, Vt, [Fe/H]) derivations).
As explained in section 3, abundances of Dy, Gd, and Th were derived
in the LTE approximation with a new modified stars LTE ssp code, we
fitted synthetic and observed spectra. For Gd II lines 4037.89,
4085.56, 4483.33Å, and Dy II lines 4073.12, 4077.97, 4103.31, and
4449.70 Å, and Th II 4019.12 Å. The oscillator strengths
log(gf) were adopted from last version of the VALD database
where a list of lines from hyperfine structure were involved for Th
element. Further in section 3.1, we constructed abundance errors. The
stellar parameters and obtained Gd, Dy, and Th abundances with the
statistical uncertainties associated from line-to-line abundance
variation are given in tablea1.dat (i.e see also section 4 for
comparison between results and galactic chemical evolution models).
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
tablea1.dat 72 276 Stellar parameters and Gd, Dy, and Th abundances
with the std from line-to-line abund variation
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See also:
J/MNRAS/340/304 : [X/Fe] of Galactic disc F and G dwarfs (Reddy+, 2003)
J/MNRAS/474/2580 : Temporal evolution of neutron-capture elements (Spina+,2018)
J/MNRAS/482/1690 : Thorium in solar twins (Botelho+, 2019)
J/MNRAS/489/1697 : Galactic disc enrichment with Mo and Ru (Mishenina+, 2019)
J/A+A/411/559 : Effective temperature for 181 F-K dwarfs (Kovtyukh+, 2003)
J/A+A/418/551 : Galactic disk stars abundances and velocities
(Mishenina+, 2004)
J/A+A/433/185 : Detailed abundance analysis of 102 F and G dwarfs
(Bensby+, 2005)
J/A+A/439/129 : HERES II. Spectroscopic analysis (Barklem+, 2005)
J/A+A/440/1153 : Equivalent widths of 7 thin-disk stars (del Peloso+, 2005)
J/A+A/489/923 : Abundances of stars in lower main sequence (Mishenina+,2008)
J/A+A/552/A128 : Stellar abundances of neutron-capture elements
(Mishenina+, 2013)
J/A+A/569/A43 : HE 2252-4225 abundance analysis (Mashonkina+, 2014)
J/A+A/619/A143 : r-process abundances in AMBRE stars (Guiglion+, 2018)
J/A+A/643/A49 : Linelist (Hansen+, 2020)
J/ApJ/724/975 : Heavy elements abundances of metal-poor stars
(Roederer+, 2010)
J/ApJ/762/26 : Most metal-poor stars. II. 190 Galactic halo stars
(Yong+, 2013)
J/ApJ/787/10 : Solar s-process contributions with GCE model
(Bisterzo+, 2014)
J/ApJ/858/92 : RPA Southern Pilot Search of 107 Stars (Hansen+, 2018)
J/ApJ/868/110 : R-Process Alliance: 1st release in Galactic halo
(Sakari+, 2018)
J/ApJ/870/2 : PUSH CCSN to explosions in spherical symmetry. III.
(Curtis+, 2019)
J/ApJ/882/40 : Lanthanide fraction distribution of metal-poor stars
(Ji+, 2019)
J/ApJ/908/79 : The r-process Alliance; abundances in 519 stars
(Gudin+, 2021)
J/ApJS/237/13 : Models and yields of 13-120M☉ massive stars
(Limongi+, 2018)
J/AJ/147/136 : Stars of very low metal abundance. VI. Abundances
(Roederer+, 2014)
Byte-by-byte Description of file: tablea1.dat
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Bytes Format Units Label Explanations
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1- 15 A15 --- n_Name Galactic location name (1)
17- 24 A8 --- Name HD/BD star name number (HD/BD)
26- 29 I4 K Teff Effective temperature from Mishenina et al.
2013A&A...552A.128M 2013A&A...552A.128M, Cat. J/A+A/552/A128
(Teff)
31- 34 F4.2 [cm/s2] logg Logarithm of surface gravity from
Mishenina et al. 2013A&A...552A.128M 2013A&A...552A.128M,
Cat. J/A+A/552/A128 (logg)
36- 40 F5.2 [Sun] [Fe/H] Iron to hydrogen abundance ratio from
Mishenina et al. 2013A&A...552A.128M 2013A&A...552A.128M,
Cat. J/A+A/552/A128 ([Fe/H])
42- 44 F3.1 km/s Vt Micro-turbulent velocity (Vt)
46- 50 F5.2 [Sun] [Gd/Fe] ? Gadolinium heavy r-process element to iron
abundance ratio ([Gd/Fe])
52- 55 F4.2 [Sun] s_[Gd/Fe] ? Standard deviation of [Gd/Fe]
(Standarddeviation[Gd/Fe])
57- 61 F5.2 [Sun] [Dy/Fe] ? Dysprosium heavy r-process element to iron
abundance ratio ([Dy/Fe])
63- 66 F4.2 [Sun] s_[Dy/Fe] ? Standard deviation of [Dy/Fe]
(Standarddeviation[Dy/Fe])
68- 72 F5.2 [Sun] [Th/Fe] ? Thorium heavy r-process element to iron
abundance ratio ([Th/Fe])
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Note (1): Locations in MW galactic disk are as follows:
Hercules-stream = Hercules stars moving group, 16 stars in the sample
thick-disc = Milky Way thick-disc stars, 21 stars in the sample
thin-disc = Milky Way thin-disc stars, 212 stars in the sample
Non-classified = Stars not in galactic discs, 27 stars in the sample
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History:
From electronic version of the journal
(End) Luc Trabelsi [CDS] 12-Aug-2025