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

Abstract

Observations of the Milky Way's low-$\alpha$ disk show that at fixed metallicity, [Fe/H], several element abundance, [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, ${\sigma }_{int}$ (0.01-0.04 dex). This ${\sigma }_{int}$ measured in the simulations is also metallicity-dependent, with ${\sigma }_{int}$ $\approx$ 0.025 dex at [Fe/H]=-0.25 dex versus ${\sigma }_{int}$ $\approx$ 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 ${\sigma }_{int}$ 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.

27 pages, 13 figures. Submitted to ApJ

References in corpus (32)

• Array Programming with NumPy
• The Astropy Project: Sustaining and Growing a Community-oriented Open-source Project and the Latest Major Release (v5.0) of the Core Package
• The GALAH Survey: Scientific Motivation
• Chemical enrichment in cosmological, smoothed particle hydrodynamics simulations
• The KMOS^3D Survey: design, first results, and the evolution of galaxy kinematics from 0.7<z<2.7
• Riding the Spiral Waves: Implications of Stellar Migration for the Properties of Galactic Disks
• The APOKASC Catalog: An Asteroseismic and Spectroscopic Joint Survey of Targets in the Kepler Fields
• 4MOST: Project overview and information for the First Call for Proposals
• High-precision abundances of elements in solar twin stars: Trends with stellar age and elemental condensation temperature
• Tracing chemical evolution over the extent of the Milky Way's Disk with APOGEE Red Clump Stars
• Vertical distribution of Galactic disk stars IV - AMR and AVR from clump giants
• The Structure and Dynamical Evolution of the Stellar Disk of a Simulated Milky Way-Mass Galaxy
• Disentangling the Galactic Halo with APOGEE: I. Chemical and Kinematical Investigation of Distinct Metal-Poor Populations
• Abundance to age ratios in the HARPS-GTO sample with Gaia DR2: Chemical clocks for a range of [Fe/H]
• The TESS-HERMES survey Data Release 1: high-resolution spectroscopy of the TESS southern continuous viewing zone
• Age velocity dispersion relations and heating histories in disc galaxies
• The imprint of clump formation at high redshift. I. A disc alpha-abundance dichotomy
• The Radical Consequences of Realistic Satellite Orbits for the Heating and Implied Merger Histories of Galactic Disks
• The Gaia-ESO survey: the non-universality of the age-chemical-clocks-metallicity relations in the Galactic disc
• High-precision abundances of Sc, Mn, Cu, and Ba in solar twins. Trends of element ratios with stellar age
• The bursty origin of the Milky Way thick disc
• Chemical abundances of 1111 FGK stars from the HARPS GTO planet search program IV. Carbon and C/O ratios for Galactic stellar populations and planet hosts
• The age-chemical abundance structure of the Galactic disc II: $\alpha$-dichotomy and thick disc formation
• Abundance-age relations with red clump stars in open clusters
• 3-D gas-phase elemental abundances across the formation histories of Milky Way-mass galaxies in the FIRE simulations: initial conditions for chemical tagging
• The age-metallicity relation in the solar neighbourhood from a pilot sample of white dwarf-main sequence binaries
• Yule-Simpson's paradox in Galactic Archaeology
• Exploring metallicity-dependent rates of Type Ia supernovae and their impact on galaxy formation
• Universal properties of the high- and low-α disk: small intrinsic abundance scatter and migrating stars
• The consistency of chemical clocks among coeval stars
• Tracing birth properties of stars with abundance clustering
• The VIRUS-P Exploration of Nearby Galaxies (VENGA): The stellar populations and assembly of NGC 2903's bulge, bar, and outer disc

Cited by in corpus (7)

• Unveiling the time evolution of chemical abundances across the Milky Way disk with APOGEE
• (Re)mind the gap: a hiatus in star formation history unveiled by APOGEE DR17
• Empirical derivation of the metallicity evolution with time and radius using TNG50 Milky Way/Andromeda analogues
• Evolution of the radial ISM metallicity gradient in the Milky Way disk since redshift $\approx 3$
• Mock Observations: Formation and Evolution of diffuse light in Galaxy Groups and Clusters in the IllustrisTNG Simulations
• The chemical enrichment of the Milky Way disk evaluated using conditional abundances
• A path towards constraining the evolution of the interstellar medium and outflows in the Milky Way using APOGEE