Chaos reigns | Nature Astronomy

Chaos reigns | Nature Astronomy

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Access through your institution Buy or subscribe A cluster of more than 100 stars in the Galactic Centre called the ‘S stars’ move visibly along their trajectories on human timescales. Predicting their movements with a high degree of accuracy is challenging due to a large number of close encounters, which induce perturbations that cause abrupt changes in orbital energies. Simon Portegies Zwart and colleagues have performed a suite of high-precision _N_-body calculations without round-off errors for the orbits of 27 members of the S-star cluster, but find that, due to the inherent chaos of the system, solutions are not accurate beyond ~500 years into the future. In comparison, the orbits of most Solar System bodies are predictable with confidence on a 12-million-year timescale. The researchers find that, over many runs of the same Newtonian model with slightly different initial conditions (such as displacing a star by 15 m in a particular direction), it is the close encounters between stars that drive the uncertainty in the predictions. Gravitational interactions between two or three nearby stars lead to slightly different stellar orbits, which produce a different ‘push’ on the Milky Way’s central supermassive black hole. This push in turn is transmitted to all stars in the cluster, leading to positions that differ by up to 40 au in different configurations of the model. In this situation the chaotic behaviour is driven by ‘instantaneous’ events — ‘punctuated chaos’, using the authors’ term — rather than being resonance-driven. This is a preview of subscription content, access via your institution ACCESS OPTIONS Access through your institution Access Nature and 54 other Nature Portfolio journals Get Nature+, our best-value online-access subscription $29.99 / 30 days cancel any time Learn more Subscribe to this journal Receive 12 digital issues and online access to articles $119.00 per year only $9.92 per issue Learn more Buy this article * Purchase on SpringerLink * Instant access to full article PDF Buy now Prices may be subject to local taxes which are calculated during checkout ADDITIONAL ACCESS OPTIONS: * Log in * Learn about institutional subscriptions * Read our FAQs * Contact customer support AUTHOR INFORMATION AUTHORS AND AFFILIATIONS * Nature Astronomy https://www.nature.com/natastron/ Paul Woods Authors * Paul Woods View author publications You can also search for this author inPubMed Google Scholar CORRESPONDING AUTHOR Correspondence to Paul Woods. RIGHTS AND PERMISSIONS Reprints and permissions ABOUT THIS ARTICLE CITE THIS ARTICLE Woods, P. Chaos reigns. _Nat Astron_ 7, 1147 (2023). https://doi.org/10.1038/s41550-023-02110-w Download citation * Published: 06 October 2023 * Issue Date: October 2023 * DOI: https://doi.org/10.1038/s41550-023-02110-w SHARE THIS ARTICLE Anyone you share the following link with will be able to read this content: Get shareable link Sorry, a shareable link is not currently available for this article. Copy to clipboard Provided by the Springer Nature SharedIt content-sharing initiative

Access through your institution Buy or subscribe A cluster of more than 100 stars in the Galactic Centre called the ‘S stars’ move visibly along their trajectories on human timescales.


Predicting their movements with a high degree of accuracy is challenging due to a large number of close encounters, which induce perturbations that cause abrupt changes in orbital energies.


Simon Portegies Zwart and colleagues have performed a suite of high-precision _N_-body calculations without round-off errors for the orbits of 27 members of the S-star cluster, but find


that, due to the inherent chaos of the system, solutions are not accurate beyond ~500 years into the future. In comparison, the orbits of most Solar System bodies are predictable with


confidence on a 12-million-year timescale. The researchers find that, over many runs of the same Newtonian model with slightly different initial conditions (such as displacing a star by 15 m


in a particular direction), it is the close encounters between stars that drive the uncertainty in the predictions. Gravitational interactions between two or three nearby stars lead to


slightly different stellar orbits, which produce a different ‘push’ on the Milky Way’s central supermassive black hole. This push in turn is transmitted to all stars in the cluster, leading


to positions that differ by up to 40 au in different configurations of the model. In this situation the chaotic behaviour is driven by ‘instantaneous’ events — ‘punctuated chaos’, using the


authors’ term — rather than being resonance-driven. This is a preview of subscription content, access via your institution ACCESS OPTIONS Access through your institution Access Nature and 54


other Nature Portfolio journals Get Nature+, our best-value online-access subscription $29.99 / 30 days cancel any time Learn more Subscribe to this journal Receive 12 digital issues and


online access to articles $119.00 per year only $9.92 per issue Learn more Buy this article * Purchase on SpringerLink * Instant access to full article PDF Buy now Prices may be subject to


local taxes which are calculated during checkout ADDITIONAL ACCESS OPTIONS: * Log in * Learn about institutional subscriptions * Read our FAQs * Contact customer support AUTHOR INFORMATION


AUTHORS AND AFFILIATIONS * Nature Astronomy https://www.nature.com/natastron/ Paul Woods Authors * Paul Woods View author publications You can also search for this author inPubMed Google


Scholar CORRESPONDING AUTHOR Correspondence to Paul Woods. RIGHTS AND PERMISSIONS Reprints and permissions ABOUT THIS ARTICLE CITE THIS ARTICLE Woods, P. Chaos reigns. _Nat Astron_ 7, 1147


(2023). https://doi.org/10.1038/s41550-023-02110-w Download citation * Published: 06 October 2023 * Issue Date: October 2023 * DOI: https://doi.org/10.1038/s41550-023-02110-w SHARE THIS


ARTICLE Anyone you share the following link with will be able to read this content: Get shareable link Sorry, a shareable link is not currently available for this article. Copy to clipboard


Provided by the Springer Nature SharedIt content-sharing initiative