Open star clusters and their asymmetrical tidal tails

Abstract

Stars that evaporate from their star cluster by the energy equipartition process end up either in a leading or a trailing tidal tail. In Newtonian gravitation and for open star clusters in the Solar vicinity, the tidal threshold, or prah, for escape is symmetrical, such that the leading and trailing tails are equally populated. The data by six independent teams that applied the convergent point method to map out the tidal tails of four open clusters (the Hyades, the Praesepe, Coma Berenices and COIN-Gaia13) using Gaia DR2 and DR3 are here applied to test for the expected symmetry. All tidal tails contain more stars in the leading tail. The combined confidence amounts to an 8 sigma falsification of the prah symmetry. The same test using Milgromian dynamics leads to consistency with the data. More effort needs to be exerted on this matter, but the data indicate with high confidence that the tidal prah of an open star cluster is asymmetrical with the corresponding confidence that Newtonian gravitation is falsified. Open star clusters depopulate more rapidly in Milgromian than in Newtonian dynamics and the COIN-Gaia13 cluster is here found to be nearly completely dissolved. In view of these results, the wide-binary star test and the Keplerian Galactic rotation curve finding are briefly discussed.

22 pages, 14 figures, 1 table, LaTeX, ApJ, in press; replaced version contains minor corrections for consistency with published version

References in corpus (25)

• galpy: A Python Library for Galactic Dynamics
• Galaxies as simple dynamical systems: observational data disfavor dark matter and stochastic star formation
• PeTar: a high-performance N-body code for modeling massive collisional stellar systems
• On the structure of tidal tails
• Extended stellar systems in the solar neighborhood - I. The tidal tails of the Hyades
• Detection of the Keplerian decline in the Milky Way rotation curve
• Discovery of Tidal Tails in Disrupting Open Clusters: Coma Berenices and a Neighbor Stellar Group
• A massive blow for $\Lambda$CDM $-$ the high redshift, mass, and collision velocity of the interacting galaxy cluster El Gordo contradicts concordance cosmology
• Praesepe (NGC 2632) and its tidal tails
• Formation and evolution of clumpy tidal tails around globular clusters
• Asymmetrical tidal tails of open star clusters: stars crossing their cluster's prah challenge Newtonian gravitation
• Extended stellar systems in the solar neighborhood - III. Like ships in the night: the Coma Berenices neighbor moving group
• The formation of exponential disk galaxies in MOND
• 3D hydrodynamic simulations for the formation of the Local Group satellite planes
• Mass models of the Milky Way and estimation of its mass from the GAIA DR3 data-set
• Do the majority of stars form as gravitationally unbound?
• Numerical Solutions of the External Field Effect on the Radial Acceleration in Disk Galaxies
• The formation of early-type galaxies through monolithic collapse of gas clouds in Milgromian gravity
• On the tension between the Radial Acceleration Relation and Solar System quadrupole in modified gravity MOND
• How rare is the Bullet Cluster (in a $\Lambda$CDM universe)?
• Hydrodynamical structure formation in Milgromian cosmology
• Discovery of extended structure around open cluster COIN-Gaia 13 based on Gaia EDR3
• The Relevance of Dynamical Friction for the MW/LMC/SMC Triple System
• Virial theorem in clusters of galaxies with MOND
• The formation of compact massive relic galaxies in MOND

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