Efficient radial migration by giant molecular clouds in the first several hundred Myr after the stellar birth

Abstract

Stars in the Galactic disc, including the Solar system, have deviated from their birth orbits and have experienced radial mixing and vertical heating. By performing hydrodynamical simulations of a galactic disc, we investigate how much tracer particles, which are initially located in the disc to mimic newborn stars and the thin and thick disc stars, are displaced from initial near-circular orbits by gravitational interactions with giant molecular clouds (GMCs). To exclude the influence of other perturbers that can change the stellar orbits, such as spiral arms and the bar, we use an axisymmetric form for the entire galactic potential. First, we investigate the time evolution of the radial and vertical velocity dispersion ${\sigma }_R$ and ${\sigma }_z$ by comparing them with a power law relation of $\sigma \propto t^{\beta }$. Although the exponents $\beta$ decrease with time, they keep large values of 0.3 $\sim$ 0.6 for 1 Gyr, indicating fast and efficient disc heating. Next, we find that the efficient stellar scattering by GMCs also causes a change in angular momentum for each star and, therefore, radial migration. This effect is more pronounced in newborn stars than old disc stars; nearly 30 per cent of stars initially located on the galactic mid-plane move more than 1 kpc in the radial direction for 1 Gyr. The dynamical heating and radial migration drastically occur in the first several hundred Myr. As the amplitude of the vertical oscillation increases, the time spent in the galactic plane, where most GMCs are distributed, decreases, and the rate of an increase in the heating and migration slows down.

arXiv comment16 pages, 12 figures. Accepted for publication in MNRAS. The simulation movie can be found at https://youtu.be/Rw4EZEOtOk4

References in corpus (80)

• The Star Formation Law in Nearby Galaxies on Sub-Kpc Scales
• The Galaxy in Context: Structural, Kinematic and Integrated Properties
• The Geneva-Copenhagen survey of the Solar neighbourhood: Ages, metallicities, and kinematic properties of 14,000 F and G dwarfs
• The Milky Way Tomography with SDSS: I. Stellar Number Density Distribution
• A Multi-Code Analysis Toolkit for Astrophysical Simulation Data
• The Neutral Atomic Phases of the ISM in the Galaxy
• The mass distribution and gravitational potential of the Milky Way
• Radial Mixing in Galactic Discs
• Enzo: An Adaptive Mesh Refinement Code for Astrophysics
• New constraints on the chemical evolution of the solar neighbourhood and Galactic disc(s). Improved astrophysical parameters for the Geneva-Copenhagen Survey
• Trigonometric Parallaxes Of High-Mass Star Forming Regions: Our View Of The Milky Way
• Chemical evolution with radial mixing
• Improved Estimates of the Milky Way's Stellar Mass and Star Formation Rate from Hierarchical Bayesian Meta-Analysis
• Riding the Spiral Waves: Implications of Stellar Migration for the Properties of Galactic Disks
• Present-day cosmic abundances. A comprehensive study of nearby early B-type stars and implications for stellar and Galactic evolution and interstellar dust models
• Chemodynamical evolution of the Milky Way disk I: The solar vicinity
• Physical properties of molecular clouds for the entire Milky Way disk
• A New Mechanism for Radial Migration in Galactic Disks: Spiral-Bar Resonance Overlap
• Toward a Unification of Star Formation Rate Determinations in the Milky Way and Other Galaxies
• The present-day star formation rate of the Milky-Way determined from Spitzer detected young stellar objects
• Star Formation in Disk Galaxies. I. Formation and Evolution of Giant Molecular Clouds via Gravitational Instability and Cloud Collisions
• Stars, Gas, and Dark Matter in the Solar Neighborhood
• Central Rotation Curves of Spiral Galaxies
• Three-Dimensional Distribution of the ISM in the Milky Way Galaxy: II. The Molecular Gas Disk
• Radial mixing and the transition between the thick and thin Galactic discs
• Cloud-Scale Molecular Gas Properties in 15 Nearby Galaxies
• Dynamical heating across the Milky Way disc using APOGEE and $Gaia$
• Giant Molecular Clouds in M33 -- II. High Resolution Observations
• The Gaia-ESO Survey: radial metallicity gradients and age-metallicity relation of stars in the Milky Way disk
• Estimating stellar birth radii and the time evolution of the Milky Way's ISM metallicity gradient
• Radial Migration in Disk Galaxies I: Transient Spiral Structure and Dynamics
• Vertical disc heating in Milky Way-sized galaxies in a cosmological context
• Dynamically Driven Evolution of the Interstellar Medium in M51
• Dynamics of Non-Steady Spiral Arms in Disk Galaxies
• Star Formation in Massive Clusters via the Wilkinson Microwave Anisotropy Probe and the Spitzer Glimpse Survey
• VINTERGATAN I: The origins of chemically, kinematically and structurally distinct discs in a simulated Milky Way-mass galaxy
• Measuring Radial Orbit Migration in the Milky Way Disk
• Radial mixing in the outer Milky Way disk caused by an orbiting satellite
• Thickening of galactic disks through clustered star formation
• Radial Mixing in Galactic Disks: The Effects of Disk Structure and Satellite Bombardment
• Three-Dimensional Distribution of the ISM in the Milky Way Galaxy: III. The Total Neutral Gas Disk
• Kinematic modelling of the Milky Way using the RAVE and GCS stellar surveys
• Milky Way vs Andromeda: a tale of two disks
• The formation of molecular clouds in spiral galaxies
• Age velocity dispersion relations and heating histories in disc galaxies
• The effect of radial migration on galactic disks
• Simulations of the heating of the Galactic stellar disc
• Stellar diffusion in barred spiral galaxies
• The First VERA Astrometry Catalog
• The Vertical Equilibrium of Molecular Gas in the Galactic Disk
• Excitation of coupled stellar motions in the Galactic Disk by orbiting satellites
• Fundamental relations for the velocity dispersion of stars in the Milky Way
• The Star Formation Rate of the Milky Way as seen by Herschel
• Inside Out and Upside-Down: The Roles of Gas Cooling and Dynamical Heating in Shaping the Stellar Age-Velocity Relation
• The effect of bars and transient spirals on the vertical heating in disk galaxies
• The Interstellar Medium and Star Formation in Edge-On Galaxies. II. NGC 4157, 4565, and 5907
• Bimodality of [α/Fe]-[Fe/H] distributions is a natural outcome of dissipative collapse and disc growth in Milky Way-type galaxies
• Short-lived radioisotopes in meteorites from Galactic-scale correlated star formation
• The quiescent phase of galactic disc growth
• A fundamental test for stellar feedback recipes in galaxy simulations
• Radial migration in a stellar galactic disc with thick components
• Constraints on Radial Migration in Spiral Galaxies I. Analytic Criterion for Capture at Corotation
• Momentum feedback from marginally-resolved HII regions in isolated disc galaxies
• Constraining churning and blurring in the Milky Way using large spectroscopic surveys -- an exploratory study
• Gravitational scattering of stars and clusters and the heating of the Galactic disk
• Radial Migration from Metallicity Gradient of Open Clusters and Outliers
• Constraining the solar neighbourhood age-metallicity relation from white dwarf-main sequence binaries
• The Stellar Distribution Function and Local Vertical Potential from Gaia DR2
• Constraints on Radial Migration in Spiral Galaxies - II. Angular momentum distribution and preferential migration
• Open Clusters as Tracers on Radial Migration of the Galactic Disk
• Dynamics and Morphology of the Milky Way Spiral Arms from the Metallicity Distribution and Radial Mixing
• A Dynamical Model for Clustered Star Formation in the Galactic Disk
• Properties of giant molecular clouds in the strongly barred galaxy NGC1300
• Distribution and kinematics of 26Al in the Galactic disc
• Radial migration and vertical action in N-body simulations
• Stellar scattering and the formation of exponential discs in self-gravitating systems
• Remarkable migration of the solar system from the innermost Galactic disk; a wander, a wobble, and a climate catastrophe on the Earth
• Imprints of Zero-Age Velocity Dispersions and Dynamical Heating on the Age-Velocity dispersion Relation
• Formation and evolution of the local interstellar environment: combined constraints from nucleosynthetic and X-ray data
• Orbits and action changes during star-clump encounters responsible for the origin of exponential discs in dwarf galaxies

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• A comparison of the Milky Way's recent star formation revealed by dust thermal emission and high-mass stars
• Solar System Migration Points to a Renewed Concept: Galactic Habitable Orbits
• Chemodynamic evolution of Sun-like stars in nearby moving groups
• Probing the strength of radial migration via churning by using metal-rich red giant stars from APOGEE
• Probing the origins. I. Generalised Additive Model inference of birth radii for Milky Way stars in the solar vicinity
• Bar instability and formation timescale across Toomre's $Q$ parameter and central mass concentration: slow bar formation or true stability
• Fundamental limits to orbit reconstruction due to non-conservation of stellar actions in a Milky Way-like simulation
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