Trapped orbits and solar-neighbourhood kinematics

Abstract

Torus mapping yields constants of motion for stars trapped at a resonance. Each such constant of motion yields a system of contours in velocity space at the Sun and neighbouring points. If Jeans' theorem applied to resonantly trapped orbits, the density of stars in velocity space would be equal at all intersections of any two contours. A quantitative measure of the violation of this principal is defined and used to assess various pattern speeds for a model of the bar recently fitted to observations of interstellar gas. Trapping at corotation of a bar with pattern speed in the range 33-36 /Gyr is favoured and trapping at the outer Lindblad resonance is disfavoured. As one moves around the Sun the structure of velocity space varies quite rapidly, both as regards the observed star density and the zones of trapped orbits. The data seem consistent with trapping at corotation.

arXiv commentSubmitted to MNRAS

References in corpus (36)

• Gaia Data Release 2. Summary of the contents and survey properties
• The Geneva-Copenhagen survey of the Solar neighbourhood: Ages, metallicities, and kinematic properties of 14,000 F and G dwarfs
• The mass distribution and gravitational potential of the Milky Way
• New constraints on the chemical evolution of the solar neighbourhood and Galactic disc(s). Improved astrophysical parameters for the Geneva-Copenhagen Survey
• What determines the strength and the slowdown rate of bars ?
• The Geneva-Copenhagen Survey of the Solar neighbourhood III. Improved distances, ages, and kinematics
• Constraints from Dynamical Friction on the Dark Matter Content of Barred Galaxies
• The Effect of the Outer Lindblad Resonance of the Galactic Bar on the Local Stellar Velocity Distribution
• Local kinematics of K and M giants from Coravel/Hipparcos/Tycho-2 data. Revisiting the concept of superclusters
• Gaia Data Release 2: Mapping the Milky Way disc kinematics
• The Distribution of Nearby Stars in Velocity Space Inferred from Hipparcos Data
• Bar-Halo Interaction and Bar Growth
• Proper motions and dynamics of the Milky Way globular cluster system from Gaia DR2
• Actions for axisymmetric potentials
• The GALAH survey and Gaia DR2: dissecting the stellar disc's phase space by age, action, chemistry and location
• The stellar velocity distribution in the solar neighbourhood
• Distances and parallax bias in Gaia DR2
• The origin of the Gaia phase-plane spiral
• Revisiting the Tale of Hercules: how stars orbiting the Lagrange points visit the Sun
• The Galactic Disc in Action Space as seen by Gaia DR2
• Gas flow in barred potentials - III. Effects of varying the Quadrupole
• The Pattern Speed of the Galactic Bar
• The signatures of the resonances of a large Galactic bar in local velocity space
• Signatures of resonance and phase mixing in the Galactic disc
• A Recent Lindblad Resonance in the Solar Neighbourhood
• On the ridges, undulations & streams in Gaia DR2: Linking the topography of phase-space to the orbital structure of an N-body bar
• Tracing the Hercules stream with Gaia and LAMOST: new evidence for a fast bar in the Milky Way
• Identifying resonances of the Galactic bar in Gaia DR2: I. Clues from action space
• Assessing distances and consistency of kinematics in Gaia/TGAS
• Torus mapper: a code for dynamical models of galaxies
• Orbital tori for non-axisymmetric galaxies
• The Solar neighbourhood in angle coordinates: the Hyades moving group
• Extending the Hyades
• Distribution functions for resonantly trapped orbits in the Galactic disc
• Managing resonant trapped orbits in our Galaxy
• Velocity-space substructure from nearby RAVE and SDSS stars

Cited by in corpus (40)

• Resonance sweeping by a decelerating Galactic bar
• Tree-ring structure of Galactic bar resonance
• Identifying resonances of the Galactic bar in Gaia DR2: I. Clues from action space
• Gas Dynamics in the Galaxy: Total Mass Distribution and the Bar Pattern Speed
• The stellar mass distribution of the Milky Way's bar: an analytic model
• Stellar halo substructure generated by bar resonances
• Chemo-kinematics of the Milky Way spiral arms and bar resonances: connection to ridges and moving groups in the Solar vicinity
• Dynamically constraining the length of the Milky Way bar
• Trimodal structure of Hercules stream explained by originating from bar resonances
• Identifying resonances of the Galactic bar in Gaia DR2: II. Clues from angle space
• Radial halo substructure in harmony with the Galactic bar
• Oscillating dynamical friction on galactic bars by trapped dark matter
• Chemodynamical signatures of bar resonances in the Galactic disk: current data and future prospects
• Observational Constraints of Radial Migration in the Galactic Disc Driven by the Slowing Bar
• The Milky Way's middle-aged inner ring
• Gaia DR3 features of the phase spiral and its possible relation to internal perturbations
• The Milky Way Bar Pattern Speed using Hercules and Gaia DR3
• Dynamical friction and feedback on galactic bars in the general fast-slow regime
• The HR 1614 moving group is not a dissolving cluster
• Remarkable migration of the solar system from the innermost Galactic disk; a wander, a wobble, and a climate catastrophe on the Earth
• The ACTIONFINDER: An unsupervised deep learning algorithm for calculating actions and the acceleration field from a set of orbit segments
• Our Galaxy's youngest disc
• Impact of bar resonances in the velocity-space distribution of the solar neighbourhood stars in a self-consistent $N$-body Galactic disc simulation
• Radial Wave in the Galactic Disk: New Clues to Discriminate Different Perturbations
• Could very low-metallicity stars with rotation-dominated orbits have been shepherded by the bar?
• Exploring the impact of a rapidly decelerating bar on transforming bulge orbits into disc-like orbits
• Bar-driven dispersal of Galactic substructure
• Trojan globular clusters: radial migration via trapping in bar resonances
• A non-axisymmetric potential for the Milky Way disk
• On the Migration Origin of the Hercules Moving Group with GAIA, LAMOST, APOGEE, and GALAH Surveys
• GaiaUnlimited: The old stellar disc of the Milky Way as traced by the Red Clump
• Dynamical streams in the local stellar halo
• Galactic echoes
• On the origin of the Hercules group: I. chemical signatures indicating the outer bar origin
• Stirring Things Up: Bar-induced substructures in the stellar halo of a cosmological Milky Way analogue
• On the connection between nitrogen-enhanced field stars and the Galactic globular clusters
• Dynamical Models of the Milky Way in Action Space with LAMOST DR8 and GAIA EDR3
• Self-consistent modelling of the Milky Way's Nuclear Stellar Disc
• GalPort: Investigation of the bar in action-angle space
• Perturbed distribution functions with accurate action estimates for the Galactic disc