Populating The Milky Way: Characterising Planet Demographics by Combining Galaxy Formation Simulations and Planet Population Synthesis Models

Abstract

Stellar populations and their distribution differ widely across the Galaxy, which is likely to affect planet demographics. Our local neighbourhood is dominated by young, metal-rich stars in the galactic thin disc, while the stellar halo and galactic bulge host a large fraction of older, metal-poor stars. We study the impact of these variations on planet populations in different regions of the Galaxy by combining a high-resolution galaxy formation simulation with state-of-the-art planet population synthesis models. We construct a population model to estimate occurrence rates of different planet types, based on the New Generation Planet Population Synthesis by Emsenhuber et al., 2021. We apply this to a simulated Milky Way--Analogue in the HESTIA galaxy formation simulation. We study the planet occurrence rate in the metal-rich regions of the inner Galaxy, i.e. in the galactic bulge and thin disc, and contrast them to the frequencies in the more distant, metal-poor region like the thick disc and stellar halo. We find that the planet demographics in the metal-poor regions of the Milky Way-Analogue, differ strongly from the planet populations in the more distant, metal-poor regions. The occurrence rate of giant planets ($>300 M_\bigoplus$) is 10 to 20 times larger in the thin disc compared to the thick disc, driven by the low amounts of solid material available for planet formation around metal-poor stars. Similarly, low-mass Earth-like planets around Sun-like stars are most abundant in the thick disc, being 1.5 times more frequent than in the thin disc. Moreover, low-mass planets are expected to be abundant throughout the galaxy, from the central regions to the outer halo, due to their formation processes being less dependent on stellar metallicity. The planet populations differ more strongly around Sun-like stars compared to dwarfs with masses 0.3 - 0.5 $M_{\odot }$.

arXiv comment19 pages, 13 figures, accepted by A&A. Code available at https://github.com/ChrisBoettner/skaro

References in corpus (92)

• Array Programming with NumPy
• Galactic Stellar and Substellar Initial Mass Function
• The EAGLE project: Simulating the evolution and assembly of galaxies and their environments
• Introducing the Illustris Project: Simulating the coevolution of dark and visible matter in the Universe
• The Galaxy in Context: Structural, Kinematic and Integrated Properties
• The PLATO 2.0 Mission
• Planet Occurrence within 0.25 AU of Solar-type Stars from Kepler
• Exploring the Milky Way stellar disk. A detailed elemental abundance study of 714 F and G dwarf stars in the Solar neighbourhood
• The mass distribution and gravitational potential of the Milky Way
• Towards a Deterministic Model of Planetary Formation I: a Desert in the Mass and Semi Major Axis Distributions of Extra Solar Planets
• Elemental Abundance Survey of The Galactic Thick Disk
• The Chemical Compositions of Galactic Disk F and G Dwarfs
• Giant Planet Occurrence in the Stellar Mass-Metallicity Plane
• Simulations of Galaxy Formation in a Lambda CDM Universe II: The Fine Structure of Simulated Galactic Disks
• The formation and retention of gas giant planets around stars with a range of metallicities
• Extrasolar planet population synthesis I: Method, formation tracks and mass-distance distribution
• Near-Field Cosmology with Metal-Poor Stars
• Improved Estimates of the Milky Way's Stellar Mass and Star Formation Rate from Hierarchical Bayesian Meta-Analysis
• The Horizon-AGN simulation: morphological diversity of galaxies promoted by AGN feedback
• The metal-rich nature of stars with planets
• The Mass-Metallicity Relation for Giant Planets
• Can giant planets form by direct gravitational instability?
• On the fraction of star formation occurring in bound stellar clusters
• The Galactic Thick Disk Stellar Abundances
• The California-Kepler Survey. IV. Metal-rich Stars Host a Greater Diversity of Planets
• The Metal Content of Bulge Field Stars from FLAMES-GIRAFFE Spectra. I. Stellar parameters and Iron Abundances
• An ALMA Survey of Protoplanetary Disks in the $\sigma$ Orionis Cluster
• A stellar-mass-dependent drop in planet occurrence rates
• The RAVE survey: the Galactic escape speed and the mass of the Milky Way
• Predictions of the WFIRST Microlensing Survey I: Bound Planet Detection Rates
• The Galactic Habitable Zone I. Galactic Chemical Evolution
• The Distribution of the Elements in the Galactic Disk III. A Reconsideration of Cepheids from l = 30 to 250 Degrees
• Mass and shape of the Milky Way's dark matter halo with globular clusters from Gaia and Hubble
• Using chemical tagging to redefine the interface of the Galactic disk and halo
• On the Shoulders of Giants: Properties of the Stellar Halo and the Milky Way Mass Distribution
• The New Generation Planetary Population Synthesis (NGPPS). IV. Planetary systems around low-mass stars
• Occurrence Rates of Planets orbiting FGK Stars: Combining Kepler DR25, Gaia DR2 and Bayesian Inference
• Mass Accretion Rates and Histories of Dark Matter Haloes
• The Milky Way Tomography with SDSS: III. Stellar Kinematics
• On the fine structure of the Cepheid metallicity gradient in the Galactic thin disk
• The Luminosity Profile and Structural Parameters of the Andromeda Galaxy
• An Estimate of the Age Distribution of Terrestrial Planets in the Universe: Quantifying Metallicity as a Selection Effect
• The New Generation Planetary Population Synthesis (NGPPS). I. Bern global model of planet formation and evolution, model tests, and emerging planetary systems
• Formation of planetary systems by pebble accretion and migration: Growth of gas giants
• Made-to-Measure models of the Galactic Box/Peanut bulge: stellar and total mass in the bulge region
• The VLA Nascent Disk And Multiplicity Survey of Perseus Protostars (VANDAM). IV. Free-Free Emission from Protostars: Links to Infrared Properties, Outflow Tracers, and Protostellar Disk Masses
• Carbon, nitrogen and $\alpha$-element abundances determine the formation sequence of the Galactic thick and thin disks
• Evidence of an Upper Bound on the Masses of Planets and its Implications for Giant Planet Formation
• Evidence for an Intermediate-Mass Milky Way from Gaia DR2 Halo Globular Cluster Motions
• Viscous diffusion and photoevaporation of stellar disks
• The Ages of the Thin Disk, Thick Disk, and the Halo from Nearby White Dwarfs
• The total stellar halo mass of the Milky Way
• The New Generation Planetary Population Synthesis (NGPPS). II. Planetary population of solar-like stars and overview of statistical results
• Hydrodynamical simulations of the galaxy population: enduring successes and outstanding challenges
• Searching the Entirety of Kepler Data. II. Occurrence Rate Estimates for FGK Stars
• The Hestia project: simulations of the Local Group
• The escape speed curve of the Galaxy obtained from Gaia DR2 implies a heavy Milky Way
• A revision of the solar neighbourhood metallicity distribution
• How planetary growth outperforms migration
• A stellar mass dependence of structured disks: a possible link with exoplanet demographics
• Extended distribution functions for our Galaxy
• A Super-Solar Metallicity For Stars With Hot Rocky Exoplanets
• The Lifetime of Protoplanetary Disks in a Low-Metallicity Environment
• On the "Galactic Habitable Zone"
• A Model of Habitability Within the Milky Way Galaxy
• Occurrence and Architecture of Kepler Planetary Systems as Functions of Stellar Mass and Effective Temperature
• Seeding the Galactic Centre gas stream: gravitational instabilities set the initial conditions for the formation of protocluster clouds
• Properties and occurrence rates of $Kepler$ exoplanet candidates as a function of host star metallicity from the DR25 catalog
• Evaluating Galactic Habitability Using High Resolution Cosmological Simulations of Galaxy Formation
• The Chemical Composition of the Galactic Bulge and Implications for its Evolution
• Prevalent externally-driven protoplanetary disc dispersal as a function of the galactic environment
• The New Generation Planetary Population Synthesis (NGPPS). V. Predetermination of planet types in global core accretion models
• Old, Metal-Poor Extreme Velocity Stars in the Solar Neighborhood
• Born this way: thin disc, thick disc, and isotropic spheroid formation in FIRE-2 Milky-Way-mass galaxy simulations
• Morphological decomposition of TNG50 galaxies: methodology and catalogue
• Architectures of Exoplanetary Systems. II: An Increase in Inner Planetary System Occurrence Toward Later Spectral Types for Kepler's FGK Dwarfs
• Milky Way metallicity gradient from Gaia DR2 F/1O double-mode Cepheids
• Planets Across Space and Time (PAST). III. Morphology of the Planetary Radius Valley as a Function of Stellar Age and Metallicity in the Galactic Context Revealed by the LAMOST-Gaia-Kepler Sample
• Exoplanets in the Galactic context: Planet occurrence rates in the thin disk, thick disk and stellar halo of Kepler stars
• The influence of infall on the properties of protoplanetary discs
• An Increase in Small-planet Occurrence with Metallicity for Late-type Dwarf Stars in the Kepler Field and Its Implications for Planet Formation
• Formation of Planetary Populations I: Metallicity & Envelope Opacity Effects
• Linking planetary embryo formation to planetesimal formation I: The impact of the planetesimal surface density in the terrestrial planet zone
• Small Planets in the Galactic Context: Host Star Kinematics, Iron, and $\alpha$ Element Enhancement
• Occurrence rates of small planets from HARPS: Focus on the Galactic context
• Planet formation throughout the Milky Way: Planet populations in the context of Galactic chemical evolution
• The age distribution of stars in the Milky Way bulge
• Galactic chemical evolution of exoplanet host stars: Are high-mass planetary systems young?
• A dynamics-free lower bound on the mass of our galaxy
• No Large Dependence of Planet Frequency on Galactocentric Distance
• Formation of Planetary Populations II: Effects of Initial Disk Size & Radial Dust Drift
• Spitzer Mid-infrared Study of Sh 2-208: Evolution of Protoplanetary Disks in Low-metallicity Environments

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• Exoplanets Across Galactic Stellar Populations with PLATO: Estimating Exoplanet Yields Around FGK Stars for the Thin Disk, Thick Disk and Stellar Halo
• Ariel stellar characterisation III. Fast rotators and new FGK stars in the Ariel Mission Candidate Sample
• Where in the Milky Way Do Exoplanets Preferentially Form?
• Modelling the Milky Way's exoplanet population based on cosmological galaxy simulations