The Influence of Orbital Eccentricity on Tidal Radii of Star Clusters

Abstract

We have performed N-body simulations of star clusters orbiting in a spherically symmetric smooth galactic potential. The model clusters cover a range of initial half-mass radii and orbital eccentricities in order to test the historical assumption that the tidal radius of a cluster is imposed at perigalacticon. The traditional assumption for globular clusters is that since the internal relaxation time is larger than its orbital period, the cluster is tidally stripped at perigalacticon. Instead, our simulations show that a cluster with an eccentric orbit does not need to fully relax in order to expand. After a perigalactic pass, a cluster re-captures previously unbound stars, and the tidal shock at perigalacticon has the effect of energizing inner region stars to larger orbits. Therefore, instead of the limiting radius being imposed at perigalacticon, it more nearly traces the instantaneous tidal radius of the cluster at any point in the orbit. We present a numerical correction factor to theoretical tidal radii calculated at perigalacticon which takes into consideration both the orbital eccentricity and current orbital phase of the cluster.

10 pages, 12 figures, Accepted for publication in ApJ

References in corpus (9)

• The Milky Way's Circular Velocity Curve to 60 kpc and an Estimate of the Dark Matter Halo Mass from Kinematics of ~2400 SDSS Blue Horizontal Branch Stars
• On the mass-radius relation of hot stellar systems
• The Early Expansion of Cluster Cores
• Space Velocities of Southern Globular Clusters. V. A Low Galactic Latitude Sample
• The construction of non-spherical models of quasi-relaxed stellar systems
• The Size Scale of Star Clusters
• A direct N-body model of core-collapse and core oscillations
• N-body models of globular clusters: metallicity, half-light radii and mass-to-light ratios
• Star Cluster Evolution in Dark Matter Dominated Galaxies

Cited by in corpus (49)

• Globular Cluster Streams as Galactic High-Precision Scales - The Poster Child Palomar 5
• Hubble Space Telescope proper motion (HSTPROMO) catalogs of Galactic globular clusters. II. Kinematic profiles and maps
• Dark Matter Halos in Galaxies and Globular Cluster Populations
• Radii of Young Star Clusters in Nearby Galaxies
• Back to the Future: Estimating Initial Globular Cluster Masses from their Present Day Stellar Mass Functions
• Prospects for chemically tagging stars in the Galaxy
• The state of globular clusters at birth II: primordial binaries
• Star Clusters in Evolving Galaxies
• The Relationship Between Globular Cluster Mass, Metallicity, and Light Element Abundance Variations
• Tidal radii and destruction rates of globular clusters in the Milky Way due to bulge-bar and disk shocking
• Erosion of Globular Cluster Systems: The Influence of Radial Anisotropy, Central Black Holes and Dynamical Friction
• The Effect of Orbital Eccentricity on the Dynamical Evolution of Star Clusters
• Wide-Field Hubble Space Telescope Observations of the Globular Cluster System in NGC1399
• Stellar Escape from Globular Clusters. I. Escape Mechanisms and Properties at Ejection
• Characteristic radii of the Milky Way Globular Clusters
• Observational Evidence for a Dark Side to NGC5128's Globular Cluster System
• The Effects of Orbital Inclination on the Scale Size and Evolution of Tidally Filling Star Clusters
• The role of galaxy mergers on the evolution of star clusters
• Great Balls of FIRE II: The evolution and destruction of star clusters across cosmic time in a Milky Way-mass galaxy
• The state of globular clusters at birth: emergence from the gas-embedded phase
• On the Link Between Energy Equipartition and Radial Variation in the Stellar Mass Function of Star Clusters
• Interrupted Stellar Encounters in Star Clusters
• Four pulsar discoveries in NGC 6624 by TRAPUM using MeerKAT
• Stars on the run: escaping from stellar clusters
• Radial Variation in the Stellar Mass Functions of Star Clusters
• A systematic analysis of star cluster disruption by tidal shocks -- I. Controlled N-body simulations and a new theoretical model
• From birth associations to field stars: mapping the small-scale orbit distribution in the Galactic disc
• On the tidal radius of satellites on prograde and retrograde orbits
• Tidal tails of dwarf galaxies on different orbits around the Milky Way
• Enlightening the dynamical evolution of Galactic open clusters: an approach using Gaia DR3 and analytical descriptions
• Multiple stellar population mass loss in massive Galactic globular clusters
• Globular Cluster Scale Sizes in Giant Galaxies: The Case of M87 and the Role of Orbital Anisotropy and Tidal Filling
• Testing for Dark Matter in the Outskirts of Globular Clusters
• Limits on the significant mass-loss scenario based on the globular clusters of the Fornax dwarf spheroidal galaxy
• Euclid: Early Release Observations -- Unveiling the morphology of two Milky Way globular clusters out to their periphery
• Pal 13: its moderately extended low density halo and its accretion history
• Searching for the extra-tidal stars of globular clusters using high-dimensional analysis and a core particle spray code
• Galactic orbital motions of star clusters: static versus semicosmological time-dependent Galactic potentials
• Mass loss from massive globular clusters in tidal fields
• Peeking beneath the precision floor -- II. Probing the chemo-dynamical histories of the potential globular cluster siblings, NGC 288 and NGC 362
• Globular Cluster Scale Sizes in Giant Galaxies: Orbital Anisotropy and Tidally Under-filling Clusters in M87, NGC 1399, and NGC 5128
• On the structure of Small Magellanic Cloud star clusters
• A systematic analysis of star cluster disruption by tidal shocks -- II. Predicting star cluster dissolution rates from a time-series analysis of their tidal histories
• Diving into dangerous tides: The impact of galaxy cluster tidal environments on satellite galaxy mass densities
• Ultraluminous X-ray sources in Globular Clusters
• Massive Star Clusters as sources of high-energy gamma radiation
• Evolution of star clusters on eccentric orbits: semi-analytical approach
• The dynamical evolution of the stellar clumps in the Sparkler galaxy
• Energy equipartition in Globular Clusters through the eyes of dynamical models