Dynamical model of Praesepe and its tidal tails

Abstract

Context. The dynamical evolution of open clusters in the tidal field of the Milky Way and the feeding of the disc field star population depend strongly on the initial conditions at the time of gas removal. Detailed dynamical models tailored to individual clusters help us understand the role of open clusters in the Galactic disc evolution. Aims. We present a detailed dynamical model of Praesepe, which reproduces the mass profile, the stellar mass function, and the mass segregation observed with the help of Gaia EDR3 data. Based on this model, we investigate the kinematic properties of the tidal tail stars in detail. Methods. We used direct N-body simulations along the eccentric orbit of Praesepe in the tidal field of the Milky Way, where each particle represents one star. The initial mass and size of the cluster, the dynamical state, and the initial mass function were adapted to reach the best-fitting model. Based on this model and a comparison model on a circular orbit, we analysed the stars in the tidal tails in terms of density, angular momentum, and orbit shapes. Results. Praesepe can be well reproduced by a cluster model with concentrated star formation in a supervirial state after instantaneous gas expulsion, adopting a global star formation efficiency of 17%. About 75% of the initially 7500 MSol are lost in the violent relaxation phase, and the observed mass segregation can be understood by two-body relaxation. We find that the self-gravity of the tail stars is the dominant force altering the angular momentum of the tail stars. For a typical star, the total change after escaping is about 1.6 kpc km/s. This corresponds to an offset in guiding radius of 7 pc, where tail stars contribute up to 70% to the alteration. The total radial shift of the orbit of the cluster in the Galactic plane can exceed 50 pc. This effect is not a result of the eccentricity of the orbit.

Contains 13 pages, 12 figures, and 4 Tables. Accepted for publication in A&A

References in corpus (49)

• Gaia Data Release 2. Summary of the contents and survey properties
• On the variation of the Initial Mass Function
• PARSEC: stellar tracks and isochrones with the PAdova and TRieste Stellar Evolution Code
• Local Kinematics and the Local Standard of Rest
• Evolution of asymptotic giant branch stars II. Optical to far-infrared isochrones with improved TP-AGB models
• The Milky Way Tomography with SDSS: I. Stellar Number Density Distribution
• Theoretical isochrones in several photometric systems I. Johnson-Cousins-Glass, HST/WFPC2, HST/NICMOS, Washington, and ESO Imaging Survey filter sets
• A geometric distance measurement to the Galactic Center black hole with 0.3% uncertainty
• Gaia Early Data Release 3: Photometric content and validation
• The Proper Motion of Sgr A*: II. The Mass of Sgr A*
• AGAMA: Action-based galaxy modelling architecture
• Detection of massive tidal tails around the globular cluster Pal 5 with SDSS commissioning data
• Vertical waves in the solar neighbourhood in Gaia DR2
• Detection of a 63 Degree Cold Stellar Stream in the Sloan Digital Sky Survey
• Four New Stellar Debris Streams in the Galactic Halo
• Mass segregation and fractal substructure in young massive clusters: (I) the McLuster code and method calibration
• The Discovery of Tidal Tails Around NGC 5466
• Tidal Tails of Star Clusters
• More on the structure of tidal tails
• The Hyades tidal tails revealed by Gaia DR2
• Star Cluster Evolution, Dynamical Age Estimation and the Kinematical Signature of Star Formation
• BSE versus StarTrack: implementations of new wind, remnant-formation, and natal-kick schemes in NBODY7 and their astrophysical consequences
• On the structure of tidal tails
• Extended stellar systems in the solar neighborhood - I. The tidal tails of the Hyades
• Discovery of Tidal Tails in Disrupting Open Clusters: Coma Berenices and a Neighbor Stellar Group
• Quantitative analysis of clumps in the tidal tails of star clusters
• Tidal tails around globular clusters. Are they a good tracer of cluster orbits?
• Praesepe (NGC 2632) and its tidal tails
• Formation and evolution of clumpy tidal tails around globular clusters
• Revised Geometric Estimates of the North Galactic Pole and the Sun's Height Above the Galactic Midplane
• Preparing the next gravitational million-body simulations: Evolution of single and binary stars in Nbody6++GPU, MOCCA and McLuster
• Local-Density Driven Clustered Star Formation
• Impact of a star formation efficiency profile on the evolution of open clusters
• Shape parameters of Galactic open clusters
• The Tidal Tails of 47 Tucanae
• Simulations of the Hyades
• The long-term evolution of star clusters formed with a centrally-peaked star-formation-efficiency profile
• Tidal tails of open star clusters as probes to early gas expulsion I: A semi-analytic model
• Tidal tails in the disintegrating open cluster NGC 752
• A tale of caution: the tails of NGC 752 are much longer than claimed
• Extended Tidal Tails of IC 4756 detected by {\it Gaia} EDR3
• Tidal tails of open star clusters as probes to early gas expulsion II: Predictions for Gaia
• The bound mass of Dehnen models with centrally peaked star formation efficiency
• Roche volume filling and the dissolution of open star clusters
• Collinder 135 and UBC 7: A Physical Pair of Open Clusters
• Roche volume filling of star clusters in the Milky Way
• The star cluster survivability after gas expulsion is independent of the impact of the Galactic tidal field
• A Monte Carlo study of early gas expulsion and evolution of star clusters: new simulations with the MOCCA code in the AMUSE framework
• Estimating the ages of open star clusters from properties of their extended tidal tails

Cited by in corpus (1)

• Centrally concentrated star formation in young clusters