$β$图画动字溯源时代的称谓系统
Addressing Systematics in the Traceback Age of the $β$ Pictoris Moving Group
摘要：
我们的特点的几个来源的系统误差的计算追溯年龄的$β$风景如画的移动组（$β$ PMG）的影响。我们发现，未校正的引力红移和对流蓝移偏置绝对径向速度测量的$\sim$ 0.6公里${}^{-1}$，这导致错误的年轻追溯年龄的$\sim$ 2百万年。视差、自行和径向速度测量的随机误差导致追溯年龄的额外偏倚为$\sim$ 150万年。在$β$ PMG的76个成员和候选者的完整输入样本中，运动学异常值和未解决的多个系统对天体测量和运动学数据的污染也错误地将追溯年龄降低了${\sim}$ 300万年。我们应用我们的新的数值回溯分析工具的核心样本的25个仔细审查的成员$β$ PMG使用盖亚数据发布3（DR3）的数据产品和其他运动调查。我们的方法产生的校正年龄为20.4 $\pm$ 2.5百万年，弥合运动年龄（11 $-$ 19百万年）和其他年龄测定方法，如等时线和锂耗尽边界（20 $-$ 26百万年）之间的差距。我们探索了几个可以随时间跟踪$β$ PMG的空间范围的关联大小度量，并且我们确定最小化沿着日心曲线坐标$ξ^{\prime}$的方差（即，由于$β$ PMG成员沿U轴的UVW空间速度色散较宽，这往往会使星协随时间沿$ξ^{\prime}$轴的空间增长最大化，因此，朝向银河系中心）提供的随机误差和系统误差最小。
英文摘要：
We characterize the impact of several sources of systematic errors on the computation of the traceback age of the $β$ Pictoris Moving Group ($β$PMG). We find that uncorrected gravitational redshift and convective blueshift bias absolute radial velocity measurements by $\sim$ 0.6 kms${}^{-1}$, which leads to erroneously younger traceback ages by $\sim$ 2 Myr. Random errors on parallax, proper motion, and radial velocity measurements lead to an additional bias of $\sim$ 1.5 Myr on traceback ages. Contamination of astrometric and kinematic data by kinematic outliers and unresolved multiple systems in the full input sample of 76 members and candidates of $β$PMG also erroneously lowers traceback ages by ${\sim}$ 3 Myr. We apply our new numerical traceback analysis tool to a core sample of 25 carefully vetted members of $β$PMG using Gaia Data Release 3 (DR3) data products and other kinematic surveys. Our method yields a corrected age of 20.4 $\pm$ 2.5 Myr, bridging the gap between kinematic ages (11$-$19 Myr) and other age-dating methods, such as isochrones and lithium depletion boundary (20$-$26 Myr). We explore several association size metrics that can track the spatial extent of $β$PMG over time, and we determine that minimizing the variance along the heliocentric curvilinear coordinate $ξ^{\prime}$ (i.e., toward the Galactic Center) offers the least random and systematic errors, due to the wider UVW space velocity dispersion of members of $β$PMG along the U-axis, which tends to maximize the spatial growth of the association along the $ξ^{\prime}$-axis over time.
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