J/A+A/633/L9 Linear regression fit coefficients (Jofre+, 2020)
Traits for chemical evolution in solar twins.
Trends of neutron-capture elements with stellar age.
Jofre P., Jackson H., Tucci Maia M.
<Astron. Astrophys. 633, L9 (2020)>
=2020A&A...633L...9J 2020A&A...633L...9J (SIMBAD/NED BibCode)
ADC_Keywords: Stars, G-type ; Abundances
Keywords: stars: abundances
Abstract:
The physical processes driving chemical evolution in the Milky Way can
be probed using the distribution of abundances in low-mass
FGK type stars in space phase at different times. During their final
stages of evolution, stars experience nucleosynthesis several times,
each at different timescales and producing different chemical
elements. Finding abundance ratios that have simple variations across
cosmic times therefore remains a challenge. Using the sample of 80
solar twins for which ages and abundances of 30 elements have been
measured with high precision, we searched for all possible abundance
ratio combinations that show linear trends with age. We found 55 such
ratios, all combining an n-capture element and another element
produced by different nucleosynthesis channels. We recovered the
ratios of [Y/Mg], [Ba/Mg], and [Al/Y] that have been reported
previously in the literature, and found that [C/Ba] depends most
strongly on age, with a slope of 0.049±0.003dex/Gyr. This imposes
constraints on the magnitude of the time dependency of abundance
ratios in solar twins. Our results suggest that s-process elements, in
lieu of Fe, should be used as a reference for constraining chemical
evolution models of the solar neighbourhood. Our study illustrates
that a wide variety of chemical elements measured in high-resolution
spectra is key to meeting the current challenges in understanding the
formation and evolution of our Galaxy.
Description:
The work presents the correlation between abundance ratios and ages
for a sample of 80 solar twins (including the Sun). The sample was
already analysed by Bedell et al. (2018ApJ...865...68B 2018ApJ...865...68B, Cat.
J/ApJ/865/68, and references therein) and Spina et al.
(2016A&A...593A.125S 2016A&A...593A.125S ).
The 30 different chemical elements were measured with high precision
by Bedell et al. (2018ApJ...865...68B 2018ApJ...865...68B, Cat. J/ApJ/865/68, and
references therein).
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 49 528 Linear regression fit coefficients
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See also:
J/ApJ/865/68 : Abundances for 79 Sun-like stars within 100pc (Bedell+, 2018)
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 11 A11 --- Trait Abundance ratio
14- 19 F6.3 Gyr-1 Slope Slope of linear regression fit of abundance
ratio as a function of age (in dex/Gyr)
23- 28 F6.3 --- Intercept Intercept of x=0 of linear regression fit
of abundance ratio as a function of age
35- 39 F5.3 10-2Gyr-1 e_Slope Standard error of fit in slope
45- 49 F5.3 --- r2 r2 parameter of correlation between
abundance ratio and age
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Acknowledgements:
Paula Jofre, paula.jofre(at)mail.udp.cl
Nucleo de Astronomia, Universidad Diego Portales
(End) Paula Jofre [Nucleo de Astron., UDP], Patricia Vannier [CDS] 13-Jan-2020