J/A+A/649/A126 Abundances of neutron-capture elements (Tautvaisiene+, 2021)
Abundances of neutron-capture elements in thin- and thick-disc stars in the
solar neighbourhood.
Tautvaisiene G., Viscasillas Vazquez C. Mikolaitis S., Stonkute E.,
Minkeviciute R., Drazdauskas A., Bagdonas V.
<Astron. Astrophys. 649, A126 (2021)>
=2021A&A...649A.126T 2021A&A...649A.126T (SIMBAD/NED BibCode)
ADC_Keywords: Stars, nearby ; Abundances ; Stars, ages
Keywords: Galaxy: evolution - stars: abundances - Galaxy: disk -
solar neighborhood
Abstract:
The aim of this work is to determine abundances of neutron-capture
elements for thin- and thick-disc F, G, and K stars in several
selected sky fields near the North Ecliptic Pole and to compare the
results with the Galactic chemical evolution models, to explore
elemental gradients according to stellar ages, mean galactocentric
distances, and maximum heights above the Galactic plane.
The observational data were obtained with the 1.65 meter telescope at
the Moletai Astronomical Observatory and a fibre-fed high-resolution
spectrograph covering a full visible wavelength range (4000-8500Å).
Elemental abundances were determined using a differential line-by-line
spectrum synthesis using the TURBOSPECTRUM code with the MARCS stellar
model atmospheres and accounting for the hyperfine-structure effects.
Results. We determined abundances of Sr, Y, Zr, Ba, La, Ce, Pr, Nd,
Sm, and Eu for 424 thin- and 82 thick-disc stars. The sample of
thick-disc stars shows a clearly visible decrease of [Eu/Mg] with
increasing metallicity compared to the thin-disc stars, bringing more
evidences of different chemical evolution in these two Galactic
components. Abundance correlation with age slopes for the investigated
thin-disc stars are slightly negative for the majority of s-process
dominated elements, while r-process dominated elements have positive
correlations. Our sample of thin-disc stars with ages spanning from
0.1 to 9Gyrs gives the [Y/Mg]=0.022(±0.015)-0.027(±0.003)/age[Gyr]
relation. However, for the thick-disc stars, when taking into account
also data from other studies, we found that [Y/Mg] cannot serve as an
age indicator. The radial abundance-to-iron gradients in the thin disc
are negligible for the s-process dominated elements and become
positive for the r-process dominated elements, the vertical gradients
are negative for the light s-process dominated elements and become
positive for the r-process dominated elements. In the thick disc, the
radial abundance-to-iron slopes are negligible and the vertical ones
are predominantly negative.
Description:
We used high-resolution spectra of all bright (V<8mag) F5 and cooler
stars (Teff<6500K) in several selected sky fields near the North
Ecliptic Pole including TESS northern continuous viewing zone (CVZ).
We used the 1.65m telescope at the Moletai Astronomical Observatory of
Vilnius University in Lithuania that is equipped with the
high-resolution Vilnius University Echelle Spectrograph (VUES). This
spectrograph has a wavelength coverage from 400 to 900nm. For our
work, we used the R∼68000 mode for the M spectral type stars and the
R∼36000 mode for other objects.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table2.dat 207 506 Abundances
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See also:
I/259 : The Tycho-2 Catalogue (Hog+ 2000)
Byte-by-byte Description of file:table2.dat
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Bytes Format Units Label Explanations
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1- 14 A14 --- Star Target name in Tycho-2 catalogue,
TYCNNNN-NNNN-N
16- 17 I2 h RAh Right ascension (J2000)
19- 20 I2 min RAm Right ascension (J2000)
22- 27 F6.3 s RAs Right ascension (J2000)
29 A1 --- DE- Declination sign (J2000)
30- 31 I2 deg DEd Declination (J2000)
33- 34 I2 arcmin DEm Declination (J2000)
36- 41 F6.3 arcsec DEs Declination (J2000)
43- 46 I4 K Teff Effective temperature
48- 51 F4.2 [cm/s2] logg log of surface gravity
53- 57 F5.2 [-] [FeI/H] Abundance [FeI/H]
59- 63 F5.2 [-] [Sr/H] ? Abundance [Sr/H]
65- 68 F4.2 [-] e_[Sr/H] ? Error on Sr abundance
70- 74 F5.2 [-] [Y/H] Abundance [Y/H]
76- 79 F4.2 [-] e_[Y/H] Error on Y abundance
81- 85 F5.2 [-] [ZrI/H] ? Abundance [ZrI/H]
87- 90 F4.2 [-] e_[ZrI/H] ? Error on ZrI abundance
92- 96 F5.2 [-] [ZrII/H] ? Abundance [ZrII/H]
98-101 F4.2 [-] e_[ZrII/H] ? Error on ZrII abundance
103-107 F5.2 [-] [Ba/H] ? Abundance [Ba/H]
109-113 F5.2 [-] [Ba/H]NLTE ? Abundance [Ba/H]_NLTE
115-118 F4.2 [-] e_[Ba/H] ? Error on Ba abundance
120-124 F5.2 [-] [La/H] ? Abundance [La/H]
126-129 F4.2 [-] e_[La/H] ? Error on La abundance
131-135 F5.2 [-] [Ce/H] ? Abundance [Ce/H]
137-140 F4.2 [-] e_[Ce/H] ? Error on Ce abundance
142-146 F5.2 [-] [Pr/H] ? Abundance [Pr/H]
148-151 F4.2 [-] e_[Pr/H] ? Error on Pr abundance
153-157 F5.2 [-] [Nd/H] ? Abundance [Nd/H]
159-162 F4.2 [-] e_[Nd/H] ? Error on Nd abundance
164-168 F5.2 [-] [Sm/H] ? Abundance [Sm/H]
170-173 F4.2 [-] e_[Sm/H] ? Error on Sm abundance
175-179 F5.2 [-] [Eu/H] ? Abundance [Eu/H]
181-184 F4.2 [-] e_[Eu/H] ? Error on Eu abundance
186-190 F5.2 Gyr Age ? Age of the star
192-196 F5.2 kpc RMean Mean Galactocentric distance
198-201 F4.2 kpc Zmax Maximum distance from Galactic plane
203-207 A5 --- Disc [thin thick] Galactic sub-component (1)
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Note (1): "thin": 419 occurrences; "thick": 80 occurrences.
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History:
From Sarunas Mikolaitis, sarunas.mikolaitis(at)tfai.vu.lt
Acknowledgements:
We acknowledge funding from the Research Council of Lithuania
(LMTLT) (Grant No. LAT-08/2016) and the European Social Fund via the
LMTLT grant No. 09.3.3-LMT-K-712-01- 0103). This work has made use of
data from the European Space Agency (ESA) mission Gaia
(https://www.cosmos.esa. int/gaia), processed by the Gaia Data
Processing and Analysis Consortium (DPAC,
https://www.cosmos.esa.int/ web/gaia/dpac/consortium). Funding for the
DPAC has been provided by national institutions, in particular the
institutions participating in the Gaia Multilateral Agreement. We
gratefully acknowledge Laura Magrini and Nikos Prantzos for providing
the GCE models, Alexey Mints for his help with UniDAM, Mark Taylor for
his help with TopCat, and Martin Vogelaar for his advises with the
Kapteyn Package. We thank the anonymous referee, whose constructive
review helped to improve this paper comprehensively. This research
made use of the Stilts and Topcat (Taylor 2005, 2006), Astropy 3
(Astropy Collaboration et al. 2018), galpy (Bovy 2015) and UniDAM
(Mints & Hekker 2017) astronomical tools. We have made extensive use
of the NASA ADS and SIMBAD databases.
(End) Patricia Vannier [CDS] 10-Mar-2021