Radial Migration from the Metallicity Gradient of Open Clusters and Outliers

Zhang, Hao-Peng; Chen, Yuqin; Zhao, Gang

doi:10.3847/1538-4357/ac0e92

Cited by 29 publications

(33 citation statements)

References 55 publications

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“…We compute these via a linear fit to each profile across 0 − R break and R break − R * 90 , where R break is a free parameter of the fit. While a two-component piecewise linear function does not fully capture the shape of the abundance profile in all cases, we choose this functional form motivated by observations that find a break in the abundance radial profile (for example Andrievsky et al 2004;Sestito et al 2008;Magrini et al 2009;Pancino et al 2010;Frinchaboy et al 2013;Hayden et al 2014;Korotin et al 2014;Maciel & Andrievsky 2019;Zhang et al 2021). That said, the majority of observations that find such a break do not separate stars (or star clusters) by age, so the observed breaks might not simply reflect the behavior of stars at formation, but also could be affected by radial redistribution (for example Anders et al 2017;Minchev et al 2018;Quillen et al 2018).…”

Section: We Now Show Results For [Fe/h] [Mg/h] and [Mg/fe] [Fe/hmentioning

confidence: 99%

3D elemental abundances of stars at formation across the histories of Milky Way-mass galaxies in the FIRE simulations

Bellardini,

Wetzel,

Loebman

et al. 2022

Preprint

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We characterize the 3-D spatial variations of [Fe/H], [Mg/H], and [Mg/Fe] in stars at the time of their formation, across 11 simulated Milky Way (MW)-and M31-mass galaxies in the FIRE-2 simulations, to inform initial conditions for chemical tagging. The overall scatter in [Fe/H] within a galaxy decreased with time until ≈ 7 Gyr ago, after which it increased to today: this arises from a competition between a reduction of azimuthal scatter and a steepening of the radial gradient in abundance over time. The radial gradient is generally negative, and it steepened over time from an initially flat gradient 12 Gyr ago. The strength of the present-day abundance gradient does not correlate with when the disk 'settled'; instead, it best correlates with the radial velocity dispersion within the galaxy. The strength of azimuthal variation is nearly independent of radius, and the 360 degree scatter decreased over time, from 0.17 dex at t lb = 11.6 Gyr to ∼ 0.04 dex at present day. Consequently, stars at t lb 8 Gyr formed in a disk with primarily azimuthal scatter in abundances. All stars formed in a vertically homogeneous disk, ∆[Fe/H]≤ 0.02 dex within 1 kpc of the galactic midplane, with the exception of the young stars in the inner ≈ 4 kpc at z ∼ 0. These results generally agree with our previous analysis of gas-phase elemental abundances, which reinforces the importance of cosmological disk evolution and azimuthal scatter in the context of stellar chemical tagging. We provide analytic fits to our results for use in chemical-tagging analyses.

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Section: We Now Show Results For [Fe/h] [Mg/h] and [Mg/fe] [Fe/hmentioning

confidence: 99%

3D elemental abundances of stars at formation across the histories of Milky Way-mass galaxies in the FIRE simulations

Bellardini,

Wetzel,

Loebman

et al. 2022

Preprint

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“…Moreover, to complicate the picture further, the yields of s-process elements are highly dependent on metallicity, in a non-monotonic way (see. e.g., [7,54,55]), and thus varied behaviours are expected at different Galactocentric regions, characterised by diverse star formation history and metallicity, as reflected by the presence of the radial metallicity gradient [56][57][58].…”

Section: Age Effects In the Abundances Of The S-process Elementsmentioning

confidence: 99%

The Abundance of S-Process Elements: Temporal and Spatial Trends from Open Cluster Observations

et al. 2022

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Spectroscopic observations of stars belonging to open clusters, with well-determined ages and distances, are a unique tool for constraining stellar evolution, nucleosynthesis, mixing processes, and, ultimately, Galactic chemical evolution. Abundances of slow (s) process neutron capture elements in stars that retain their initial surface composition open a window into the processes that generated them. In particular, they give us information on their main site of production, i.e., the low- and intermediate-mass Asymptotic Giant Branch (AGB) stars. In the present work, we review some observational results obtained during the last decade that contributed to a better understanding of the AGB phase: the growth of s-process abundances at recent epochs, i.e., in the youngest stellar populations; the different relations between age and [s/Fe] in distinct regions of the disc; and finally the use of s-process abundances combined with those of α elements, [s/α], to estimate stellar ages. We revise some implications that these observations had both on stellar and Galactic evolution, and on our ability to infer stellar ages.

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“…What weight migration holds in shaping the spatial distribution of more massive populations such as clusters, with respect to single stars, is not yet settled (see, e.g. Anders et al 2017;Chen & Zhao 2020;Zhang et al 2021;Netopil et al 2021).…”

Section: Role Of Migration In Open Clustersmentioning

confidence: 99%

The Gaia-ESO survey: Age-chemical-clock relations spatially resolved in the Galactic disc

Vázquez

Magrini

Casali

et al. 2022

A&A

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Context. The last decade has seen a revolution in our knowledge of the Galaxy thanks to the Gaia and asteroseismic space missions and the ground-based spectroscopic surveys. Aims. To complete this picture, it is necessary to map the ages of its stellar populations. During recent years, the dependence on time of abundance ratios involving slow (s) neutron-capture and α elements (called chemical-clocks) has been used to provide estimates of stellar ages, usually in a limited volume close to the Sun. We aim to analyse the relations of chemical clocks in the Galactic disc extending the range to R GC ∼6-20 kpc. Methods. Using the sixth internal data release of the Gaia-ESO survey, we calibrated several relations between stellar ages and abundance ratios [s/α] using a sample of open clusters, the largest one so far used with this aim (62 clusters). Thanks to their wide galactocentric coverage, we investigated the radial variations of the shape of these relations, confirming their non-universality.Results. The multi-variate relations allowed us to infer stellar ages for field stars. We estimated our accuracy (ranging from 0.0 to -0.9 Gyr) and precision (from 0.4 to 2.3 Gyr) in recovering the global ages of open clusters, and the ages of their individual members. We applied the relations with the highest correlation coefficients to the field star population, finding an older population at lower metallicity and higher [α/Fe] in the thin disc, and a younger one at higher [Fe/H] and low [α/Fe], as expected. Conclusions. We confirm that there is no single age-chemical clock relationship valid for the whole disc, but that there is a dependence on the galactocentric position, which is related to the radial variation of the star formation history combined with the non-monotonic dependence on metallicity of the yields of the s-process elements from low-and intermediate-mass stars. Finally, the abundance ratios [Ba/α] are more sensitive to age than those with [Y/α] for young disc stars, and their slopes vary less with galactocentric distance. We remind the reader that the application of such relationships to field stars is only of statistical value.

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Radial Migration from the Metallicity Gradient of Open Clusters and Outliers

Cited by 29 publications

References 55 publications

3D elemental abundances of stars at formation across the histories of Milky Way-mass galaxies in the FIRE simulations

3D elemental abundances of stars at formation across the histories of Milky Way-mass galaxies in the FIRE simulations

The Abundance of S-Process Elements: Temporal and Spatial Trends from Open Cluster Observations

The Gaia-ESO survey: Age-chemical-clock relations spatially resolved in the Galactic disc

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