标题： IC 4756的延伸潮汐尾部由{\it Gaia}EDR3检测到 显示英文标题

标题： Extended Tidal Tails of IC 4756 detected by {\it Gaia} EDR3

摘要： 我们报告了在开放星团IC 4756（$\sim$1 Gyr）周围发现的潮汐尾，这是基于从{\it Gaia}EDR3中识别出的644个成员。三维空间位置和二维切向速度$\left( x, y, z, \kappa \cdot \mu_{\alpha}^{*}/\varpi, \kappa \cdot \mu_{\delta}/\varpi \right)$被用于确定IC 4756的共动成员候选者。使用贝叶斯方法，我们校正了每个星团成员的距离。两个潮汐尾延伸至180 pc，并在$X^{\prime}Y^{\prime}$空间（聚焦于星团中心的笛卡尔坐标）中呈现S形。我们在颜色-绝对星等图（CAMD）中发现了成员的清晰序列，表明同时形成的群体，并与Bossini等人（2019）给出的年龄的PARSEC等时线完美匹配。该星团中也检测到了质量分层现象。最后，我们得出IC 4756的潮汐半径和核心半径分别为$12.13$pc和$4.33 \pm 0.75$pc。 显示英文摘要

摘要： We report the discovery of emerged tidal tails around open cluster IC 4756 ($\sim$ 1 Gyr) based on 644 members identified from {\it Gaia} EDR3. Three-dimensional spatial positions, two-dimensional tangential velocities $\left( x, y, z, \kappa \cdot \mu_{\alpha}^{*}/\varpi, \kappa \cdot \mu_{\delta}/\varpi \right)$ are utilized to determine the co-moving member candidates of IC 4756. Using a Bayesian method, we correct the distance for each cluster member. Two tidal tails extend up to 180 pc and display a S-shape in $X^{\prime}Y^{\prime}$ space (Cartesian coordinates focused on cluster center). A clean sequence of our members in Color-Absolute-Magnitude Diagram (CAMD) indicates the coeval population and matches perfectly with the PARSEC isochrone with age from Bossini et al. (2019). Mass segregation is detected in this cluster as well. Finally, we derive the tidal radius and core radius of IC 4756 about $12.13$ pc and $4.33 \pm 0.75$ pc, respectively.