The disrupting and growing open cluster spiral arm patterns of the Milky Way

Fuente: arXiv
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Main Authors: Liu, Xiaochen, He, Zhihong, Luo, Yangping, Wang, Kun
Format: Preprint
Published: 2025
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author Liu, Xiaochen
He, Zhihong
Luo, Yangping
Wang, Kun
author_facet Liu, Xiaochen
He, Zhihong
Luo, Yangping
Wang, Kun
contents Star clusters provide unique advantages for investigating Galactic spiral arms, particularly due to their precise ages, positions, and kinematic properties, which are further enhanced by ongoing updates from the astrometric data. In this study, we employ the latest extensive catalogue of open clusters from Gaia DR3 to examine the positional deviations of clusters belonging to different age groups. Additionally, we employ dynamical simulations to probe the evolutionary behavior of spiral arm positions. Our analysis reveals an absence of a theoretical age pattern in the spiral arms traced by open clusters, and the pattern speeds of the spiral arms are consistent with the rotation curve. Both of these results do not align with the predictions of quasi-stationary density wave theory, suggesting a more dynamic or transient arm scenario for the Milky Way. From this perspective, combined with vertex deviation estimates, it appears that the Local arm is in a state of growth. In contrast, the Sagittarius-Carina arm and the Perseus arm exhibit opposing trends. Consequently, we speculate that the Galactic stellar disk does not exhibit a grand-design spiral pattern with a fixed pattern speed, but rather manifests as a multi-armed structure with arms that continuously emerge and dissipate.
format Preprint
id arxiv_https___arxiv_org_abs_2501_14215
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle The disrupting and growing open cluster spiral arm patterns of the Milky Way
Liu, Xiaochen
He, Zhihong
Luo, Yangping
Wang, Kun
Astrophysics of Galaxies
Star clusters provide unique advantages for investigating Galactic spiral arms, particularly due to their precise ages, positions, and kinematic properties, which are further enhanced by ongoing updates from the astrometric data. In this study, we employ the latest extensive catalogue of open clusters from Gaia DR3 to examine the positional deviations of clusters belonging to different age groups. Additionally, we employ dynamical simulations to probe the evolutionary behavior of spiral arm positions. Our analysis reveals an absence of a theoretical age pattern in the spiral arms traced by open clusters, and the pattern speeds of the spiral arms are consistent with the rotation curve. Both of these results do not align with the predictions of quasi-stationary density wave theory, suggesting a more dynamic or transient arm scenario for the Milky Way. From this perspective, combined with vertex deviation estimates, it appears that the Local arm is in a state of growth. In contrast, the Sagittarius-Carina arm and the Perseus arm exhibit opposing trends. Consequently, we speculate that the Galactic stellar disk does not exhibit a grand-design spiral pattern with a fixed pattern speed, but rather manifests as a multi-armed structure with arms that continuously emerge and dissipate.
title The disrupting and growing open cluster spiral arm patterns of the Milky Way
topic Astrophysics of Galaxies
url https://arxiv.org/abs/2501.14215