The effects of star-gas interactions on binary evolution in open clusters
January 1, 2026·,
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Jixuan Yang
Lile Wang
Xinyu Li
Meng Sun
Long Wang
Rainer Spurzem
Abstract
Star-gas interactions can provide gravitational feedback that influences the dynamical evolution of stellar clusters, through processes such as dynamical friction (DF) and its non-dissipative counterpart, negative dynamical friction (NDF). Using the exttt{PeTar} code, we perform direct N-body simulations of an open cluster initially containing 10000 stars, evolving within a gaseous medium spanning a range of ambient densities. Our results demonstrate that NDF associated with stellar outflows interacting with the surrounding gas can enhance the rate of cluster expansion, preferentially transporting stars toward the cluster outskirts. This behavior is accompanied by a more rapid decline in the number of binaries composed of a neutron star and a main-sequence star. A statistical analysis of binary orbital parameters further indicates that, compared to DF-dominated evolution, NDF tends to retain systems with larger semi-major axes and lower eccentricities. Outflow-ambient gas interactions can modify the dynamical processing of binaries in star clusters, leading to changes in the survival fraction and composition of the remaining binary population.
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Assistant Professor
Xinyu Li is an assistant professor in the Department of Astronomy, Tsinghua University. He is fond of discovering fundamental physical laws from the vast observation of various astrophysical objects. His research areas are high energy astrophysics, plasma astrophysics and cosmology. His research topics cover a broad range of physical scales: from the smallest fundamental particles like electrons and ultralight axions, to neutron stars, black holes and galaxies, and to the largest scale structure of the universe.