The AMBRE Project: [Y/Mg] stellar dating calibration with <i>Gaia</i>

Titarenko, A.; Recio–Blanco, A.; Laverny, P. de; Hayden, Michael R.; Guiglion, G.

doi:10.1051/0004-6361/201833721

Cited by 32 publications

(39 citation statements)

References 42 publications

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“…However, when studied in solar-type stars as a function of metallicity (Feltzing et al 2017), the relation vanishes towards lower metallicities, placing a lower limit of [Fe/H] ∼ −0.5 for the relation to become flat. Later, Delgado Mena et al (2019), Titarenko et al (2019), and Casali et al (2020) also noticed a possible nonuniversality of most chemical clocks at different metallicities, spatial location, and different Galactic populations (e.g., the thick disk). Recently, Magrini et al (2021) proposed a theoretical explanation involving magnetic mixing.…”

Section: Introductionmentioning

confidence: 96%

Abundance–age relations with red clump stars in open clusters

Casamiquela

Soubiran

Jofré

et al. 2021

A&A

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Context. Precise chemical abundances coupled with reliable ages are key ingredients to understanding the chemical history of our Galaxy. Open clusters (OCs) are useful for this purpose because they provide ages with good precision. Aims. The aim of this work is to investigate the relation between different chemical abundance ratios and age traced by red clump (RC) stars in OCs. Methods. We analyzed a large sample of 209 reliable members in 47 OCs with available high-resolution spectroscopy. We applied a differential line-by-line analysis, performing a comprehensive chemical study of 25 chemical species. This sample is among the largest samples of OCs homogeneously characterized in terms of atmospheric parameters, detailed chemistry, and age. Results. In our metallicity range (−0.2 < [M/H] < +0.2) we find that while most Fe-peak and α elements show a flat dependence on age, the s-process elements show a decreasing trend with increasing age with a remarkable knee at 1 Gyr. For Ba, Ce, Y, Mo, and Zr, we find a plateau at young ages (< 1 Gyr). We investigate the relations between all possible combinations among the computed chemical species and age. We find 19 combinations with significant slopes, including [Y/Mg] and [Y/Al]. The ratio [Ba/α] shows the most significant correlation. Conclusions. We find that the [Y/Mg] relation found in the literature using solar twins is compatible with the one found here in the solar neighborhood. The age–abundance relations in clusters at large distances(d > 1 kpc) show larger scatter than those in clusters in the solar neighborhood, particularly in the outer disk. We conclude that, in addition to pure nucleosynthetic arguments, the complexity of the chemical space introduced by the Galactic dynamics must be taken into account in order to understand these relations, especially outside of the local bubble.

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Section: Introductionmentioning

confidence: 96%

Abundance–age relations with red clump stars in open clusters

Casamiquela

Soubiran

Jofré

et al. 2021

A&A

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“…Therefore it would be very useful to find abundance ratios that could be used as a proxy for age (e.g., Nissen & Gustafsson 2018;Silva Aguirre et al 2018). Although [Y/Mg] is very promising as such a "chemical clock", observations indicate that the correlation with age might depend on metallicity (Feltzing et al 2017) and/or environment, because some differences are seen between the thick and thin disks (Delgado Mena et al 2019;Titarenko et al 2019). This raises the question of how universal these chemical clocks are, especially because they have currently not been studied in other galaxies.…”

Section: Introductionmentioning

confidence: 99%

Neutron-capture elements in dwarf galaxies

Skúladóttir

Hansen

Salvadori

et al. 2019

A&A

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The heavy elements (Z > 30) are created in neutron (n)-capture processes that are predicted to happen at vastly different nucleosynthetic sites. To study these processes in an environment different from the Milky Way, we targeted the n-capture elements in red giant branch stars in the Sculptor dwarf spheroidal galaxy. Using ESO VLT/FLAMES spectra, we measured the chemical abundances of Y, Ba, La, Nd, and Eu in 98 stars covering the metalliticy range −2.4 < [Fe/H] < −0.9. This is the first paper in a series about the n-capture elements in dwarf galaxies, and here we focus on the relative and absolute timescales of the slow (s)- and rapid (r)-processes in Sculptor. From the abundances of the s-process element Ba and the r-process element Eu, it is clear that the r-process enrichment occurred throughout the entire chemical evolution history of Sculptor. Furthermore, there is no evidence for the r-process to be significantly delayed in time relative to core-collapse supernovae. Neutron star mergers are therefore unlikely the dominant (or only) nucleosynthetic site of the r-process. However, the products of the s-process only become apparent at [Fe/H] ≈ −2 in Sculptor, and the s-process becomes the dominant source of Ba at [Fe/H] ≳ −2. We tested the use of [Y/Mg] and [Ba/Mg] as chemical clocks in Sculptor. Similarly to what is observed in the Milky Way, [Y/Mg] and [Ba/Mg] increase towards younger ages. However, there is an offset in the trends, where the abundance ratios of [Y/Mg] in Sculptor are significantly lower than those of the Milky Way at any given age. This is most likely caused by metallicity dependence of yields from the s-process, as well as by a different relative contribution of the s-process to core-collapse supernovae in these galaxies. Comparisons of our results with data of the Milky Way and the Fornax dwarf spheroidal galaxy furthermore show that these chemical clocks depend on both metallicity and environment.

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“…Mg] are precise age indicators in the case of solar twins stars. These are the so called chemical clocks and have been studied in other samples of solar twins(Spina et al 2016;Tucci Maia et al 2016) and very recently, in a bigger sample of stars within the AMBRE project(Titarenko et al 2019). Moreover, these chemical clocks working over solar twin stars where confirmed using stars dated by asteroseismology(Nissen et al 2017).…”

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confidence: 97%

Abundance to age ratios in the HARPS-GTO sample with Gaia DR2

Mena

Moya

Adibekyan

et al. 2019

A&A

116

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Aims. The purpose of this work is to evaluate how several elements produced by different nucleosynthesis processes behave with stellar age and provide empirical relations to derive stellar ages from chemical abundances. Methods. We derived different sets of ages using Padova and Yonsei-Yale isochrones and HIPPARCOS and Gaia parallaxes for a sample of more than 1000 FGK dwarf stars for which he have high-resolution (R ∼ 115 000) and high-quality spectra from the HARPS-GTO program. We analyzed the temporal evolution of different abundance ratios to find the best chemical clocks. We applied multivariable linear regressions to our sample of stars with a small uncertainty on age to obtain empirical relations of age as a function of stellar parameters and different chemical clocks.Results. We find that [α/Fe] ratio (average of Mg, Si, and Ti), [O/Fe] and [Zn/Fe] are good age proxies with a lower dispersion than the age-metallicity dispersion. Several abundance ratios present a significant correlation with age for chemically separated thin disk stars (i.e., low-α) but in the case of the chemically defined thick disk stars (i.e., high-α) only the elements Mg, Si, Ca, and Ti II show a clear correlation with age. We find that the thick disk stars are more enriched in light-s elements than thin disk stars of similar age. The maximum enrichment of s-process elements in the thin disk occurs in the youngest stars which in turn have solar metallicity. The slopes of the [X/Fe]-age relations are quite constant for O, Mg, Si, Ti, Zn, Sr, and Eu regardless of the metallicity. However, this is not the case for Al, Ca, Cu and most of the s-process elements, which display very different trends depending on the metallicity. This demonstrates the limitations of using simple linear relations based on certain abundance ratios to obtain ages for stars of different metallicities. Finally, we show that by using 3D relations with a chemical clock and two stellar parameters (either T eff , [Fe/H] or stellar mass) we can explain up to 89% of age variance in a star. A similar result is obtained when using 2D relations with a chemical clock and one stellar parameter, explaining up to a 87% of the variance. Conclusions. The complete understanding of how the chemical elements were produced and evolved in the Galaxy requires the knowledge of stellar ages and precise chemical abundances. We show how the temporal evolution of some chemical species change with metallicity, with remarkable variations at super-solar metallicities, which will help to better constrain the yields of different nucleosynthesis processes along the history of the Galaxy.

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The AMBRE Project: [Y/Mg] stellar dating calibration with Gaia

Cited by 32 publications

References 42 publications

Abundance–age relations with red clump stars in open clusters

Abundance–age relations with red clump stars in open clusters

Neutron-capture elements in dwarf galaxies

Abundance to age ratios in the HARPS-GTO sample with Gaia DR2

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