发表机构
Instituto Interdisciplinario de Ciencias Básicas (ICB), CONICET-UNCuyo; Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET)（基础科学跨研究所; 国家科学技术研究委员会）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
本研究通过分析155个邻近疏散星团的潮汐尾错位，发现新生潮汐尾在旋臂间隙内出现大角度错位，可作为共转共振区非轴对称银河系势的高分辨率示踪体。
AI 中文摘要
传统上，疏散星团的潮汐尾被认为因银河系剪切作用而与其轨道运动方向对齐。然而，近期观测表明，相当数量的星团展现出错位的潮汐尾，其起源至今仍知之甚少。我研究了太阳附近1千秒差距内155个邻近疏散星团样本的潮汐尾结构特性，以刻画非轴对称银河系扰动体对恒星剥离过程的影响。利用高精度盖亚DR3天体测量数据和概率成员判定，我追踪了潮汐尾的主要取向和物理长度。通过分析错位角（DeltaPA）相对于本地旋臂边界的空间分布，并将结果与近期关于棒旋和旋臂势的测试粒子模拟进行比较，我区分了局域与全局扰动。我识别出三种不同的动力学状态。虽然大多数星团的潮汐尾与剪切对齐，但相当一部分子样本展现出空间上无差别的背景错位（10度<DeltaPA<30度），这与全局银河系棒力矩作用一致。相反，一群新生潮汐尾（长度<0.3千秒差）展现出更大的错位（DeltaPA>40度），并具有独特的空间特异性，仅出现在旋臂间隙内（|d_arm|>0.2千秒差）。这些显著错位可能代表了共转共振零剪切区内发生的瞬态动力学阶段，在此区域，旋臂势的径向引力作用通过旋转潮汐张量的特征向量主导恒星逃逸轨迹。这可能将新生潮汐尾识别为对非轴对称银河系势具有独特敏感性的高分辨率示踪体。
英文摘要
Tidal tails of open clusters are traditionally expected to align with their orbital motion due to Galactic shear. However, recent observations suggest that a significant population of clusters exhibits misaligned tails, the origin of which remains poorly understood. I investigate the structural properties of tidal tails for a sample of 155 nearby open clusters within 1 kpc of the Sun to characterize the influence of non-axisymmetric Galactic perturbers on stellar stripping geometry.Using high-precision Gaia DR3 astrometry and the probabilistic membership, I trace the primary orientation and physical length of tidal tails. I distinguish between local and global perturbations by analyzing the spatial distribution of misalignment (DeltaPA) relative to the boundaries of the Local Arm and comparing results with recent test-particle simulations of barred and spiral potentials. I identify three distinct dynamical regimes. While the majority of the population is shear-aligned, a significant subset exhibits a spatially indifferent background misalignment (10deg < DeltaPA < 30deg) consistent with global Galactic bar torques. In contrast, a population of nascent tails (< 0.3 kpc) exhibits larger misalignments (DeltaPA > 40deg) with a unique spatial specificity, occurring exclusively within the inter-arm gaps (|d_arm| > 0.2 kpc). These significant misalignments could represent a transient dynamical phase occurring within the corotation resonance's zero-shear zone, where the radial gravitational forcing of the spiral potential dominates stellar exit trajectories by rotating the eigenvectors of the tidal tensor. This could identify nascent tidal tails as uniquely sensitive high-resolution tracers of the non-axisymmetric Galactic potential.
Comments9 pages, 6 figures. Accepted for publication in A&A
