Neutron-capture elements record the ordered chemical evolution of the disc over time

Horta, Danny; Ness, Melissa K.; Rybizki, Jan; Schiavon, Ricardo P.; Buder, Sven

doi:10.48550/arxiv.2111.01809

Cited by 4 publications

(4 citation statements)

References 141 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Several further works have contributed to the understanding of the origin of this growth, without yet reaching a general consensus, arguing whether the enrichment is due to mixing effects that produce a larger source of neutrons, and hence s-elements, in low-mass stars, or whether it is due to observational effects or related to stellar characteristics, such as chromospheric or magnetic activity (see, e.g., Busso et al [9], Bisterzo et al [25], Mishenina et al [26], Trippella et al [27], Reddy and Lambert [28], Magrini et al [29], Spina et al [30,31], Baratella et al [32]). Other works used the properties of those abundance ratios as a valuable tool to estimate the ages of stars (see, e.g., Spina et al [30], Nissen [33], Delgado Mena et al [34], Casali et al [35], Horta et al [36]).…”

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

View full text Add to dashboard Cite

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.

show abstract

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

View full text Add to dashboard Cite

show abstract

“…Additionally, comparisons between the slope in the [Fe/H]-[X/Fe] relation and the slope in the age-[X/Fe] relation appear to group elements accordingly into three distinct nucleosynthetic sites: core-collapse supernova (SNe II), white dwarf explosion (SNIa), and stellar winds (Sharma et al 2022). Furthermore, the slope in the age-[X/Fe] relation is sensitive to the location across the [Mg/Fe] vs [Fe/H] plane (Yuxi et al 2021;Horta et al 2021), but the scatter around these relations is consistently small. Both the high resolution studies at [Fe/H] = 0 dex from Nissen (2015) and Bedell et al (2018) as well as the larger samples exploring a wider range of metallicities (Ness et al 2019;Sharma et al 2022) have shown that the intrinsic scatter of stars around their age-[X/Fe] relations is on the order of < 0.01-0.04 dex.…”

Section: Introductionmentioning

confidence: 99%

The relationship between age, metallicity, and abundances for disk stars in a simulated Milky Way galaxy

Carrillo¹,

Ness²,

Hawkins³

et al. 2022

Preprint

Self Cite

View full text Add to dashboard Cite

Observations of the Milky Way's low-α disk show that at fixed metallicity, [Fe/H], several element abundances, [X/Fe], correlate with age, with unique slopes and small scatters around the age-[X/Fe] relations. In this study, we turn to simulations to explore the age-[X/Fe] relations for the elements C, N, O, Mg, Si, S, and Ca that are traced in a FIRE-2 cosmological zoom-in simulation of a Milky-Way like galaxy, m12i, and understand what physical conditions give rise to the observed age-[X/Fe] trends. We first explore the distributions of mono-age populations in their birth and current locations, [Fe/H], and [X/Fe], and find evidence for inside-out radial growth for stars with ages < 7 Gyr. We then examine the age-[X/Fe] relations across m12i's disk and find that the direction of the trends agree with observations, apart from C, O, and Ca, with remarkably small intrinsic scatters, σ int (0.01 − 0.04 dex). This σ int measured in the simulations is also metallicity-dependent, with σ int ≈ 0.025 dex at [Fe/H] = −0.25 dex versus σ int ≈ 0.015 dex at [Fe/H] = 0 dex, and a similar metallicity dependence is seen in the GALAH survey for the elements in common. Additionally, we find that σ int is higher in the inner galaxy, where stars are older and formed in less chemically-homogeneous environments. The age-[X/Fe] relations and the small scatter around them indicate that simulations capture similar chemical enrichment variance as observed in the Milky Way, arising from stars sharing similar element abundances at a given birth place and time.

show abstract

“…While some chemical thin disc stars may be found in the geometric thick disc, it is characterized by old, α-enhanced, and kinematically hot populations, while the geometric thin disc mostly consist of younger, solar-α, and kinematically cooler populations (e.g., Bensby et al 2005;Lian et al 2020b). This connection between the geometric and chemical dichotomy implies close relation between the thick/thin disc structure formation and the chemical evolution history of the Galaxy (Lian et al 2020b;Horta et al 2021).…”

Section: Introductionmentioning

confidence: 87%

The Milky Way tomography with APOGEE: intrinsic density distribution and structure of mono-abundance populations

Lian,

Zasowski,

Mackereth

et al. 2022

Preprint

Self Cite

View full text Add to dashboard Cite

The spatial distribution of mono-abundance populations (MAPs, selected in [Fe/H] and [Mg/Fe]) reflect the chemical and structural evolution in a galaxy and impose strong constraints on galaxy formation models. In this paper, we use APOGEE data to derive the intrinsic density distribution of MAPs in the Milky Way, after carefully considering the survey selection function. We find that a single exponential profile is not a sufficient description of the Milky Way's disc. Both the individual MAPs and the integrated disc exhibit a broken radial density distribution; densities are relatively constant with radius in the inner Galaxy and rapidly decrease beyond the break radius. We fit the intrinsic density distribution as a function of radius and vertical height with a 2D density model that considers both a broken radial profile and radial variation of scale height (i.e., flaring). There is a large variety of structural parameters between different MAPs, indicative of strong structure evolution of the Milky Way. One surprising result is that high-α MAPs show the strongest flaring. The young, solar-abundance MAPs present the shortest scale height and least flaring, suggesting recent and ongoing star formation confined to the disc plane. Finally we derive the intrinsic density distribution and corresponding structural parameters of the chemically defined thin and thick discs. The chemical thick and thin discs have local surface mass densities of 5.62±0.08 and 15.69±0.32 M pc −2 , respectively, suggesting a massive thick disc with a local surface mass density ratio between thick to thin disc of 36%.

show abstract

Neutron-capture elements record the ordered chemical evolution of the disc over time

Cited by 4 publications

References 141 publications

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

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

The relationship between age, metallicity, and abundances for disk stars in a simulated Milky Way galaxy

The Milky Way tomography with APOGEE: intrinsic density distribution and structure of mono-abundance populations

Contact Info

Product

Resources

About