Abstract

We have studied the kinematics of a unique sample of young open star clusters (OSCs) with high vertical velocities, \(15<W<40\) km s\({}^{-1}\). The characteristics of these clusters were taken from the catalogue by Hunt and Reffert (2023), where their mean proper motions, line-of-sight velocities, and distances were calculated using Gaia DR3 data. These OSCs are located within 0.6 kpc of the Sun and form two clumps: one in the region of the Sco–Cen OB association and the other one in the region of the Per OB3–Per OB2 associations. The OSC group of 47 members in the region of the Sco–Cen association is shown to expand along the \(y\) axis, \(\partial V/\partial y=51\pm 12\) km s\({}^{-1}\) kpc\({}^{-1}\). This group also has a positive rotation around the \(z\) axis with an angular velocity of \(71\pm 11\) km s\({}^{-1}\) kpc\({}^{-1}\) and a negative rotation around the \(x\) axis with an angular velocity of \(-35\pm 5\) km s\({}^{-1}\) kpc\({}^{-1}\). Based on the velocities of 27 OSCs from the region of the Per OB3–Per OB2 associations, we have found no gradients differing significantly from zero. We have studied the kinematics of more than 1700 stars selected by Luhman (2022) as probable members of the Sco–Cen OB association. These stars are shown to have no high vertical velocities. The expansion coefficient of the stellar system in the \(xy\) plane has been found from all stars to be \(K_{xy}=43.2\pm 2.2\) km s\({}^{-1}\) kpc\({}^{-1}\). Based on stars from the three UCL, LCC, and V1062 Sco groups with a mean age \({\sim}20\) Myr, for the first time we have found a volume expansion coefficient of the stellar system differing significantly from zero, \(K_{xyz}=43.2\pm 3.4\) km s\({}^{-1}\) kpc\({}^{-1}\).

中文翻译：

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Sco-Cen OB 协会区域高垂直速度疏散星团的特性

摘要

我们研究了具有高垂直速度\(15<W<40\) km s \({}^{-1}\)的年轻疏散星团 (OSC) 的独特样本的运动学。这些星团的特征取自 Hunt 和 Reffert (2023) 的星表，其中它们的平均自行、视线速度和距离是使用 Gaia DR3 数据计算的。这些 OSC 位于距太阳 0.6 kpc 范围内，并形成两个团块：一个在 Sco-Cen OB 协会区域，另一个在 Per OB3-Per OB2 协会区域。Sco–Cen 协会区域内由 47 个成员组成的 OSC 小组显示沿\(y\)轴扩展，\(\partial V/\partial y=51\pm 12\) km s \({} ^{-1}\) kpc \({}^{-1}\)。该群还绕\(z\)轴正旋转，角速度为\(71\pm 11\) km s \({}^{-1}\) kpc \({}^{-1 }\)并绕\(x\)轴负旋转，角速度为\(-35\pm 5\) km s \({}^{-1}\) kpc \({}^{- 1}\) . 根据来自 Per OB3–Per OB2 关联区域的 27 个 OSC 的速度，我们发现没有与零显着不同的梯度。我们研究了 Luhman (2022) 选出的 1700 多颗恒星的运动学，这些恒星可能是 Sco-Cen OB 协会的成员。这些恒星被证明没有很高的垂直速度。从所有恒星中发现恒星系统在\(xy\)平面的膨胀系数为\(K_{xy}=43.2\pm 2.2\) km s \({}^{-1}\) kpc \({}^{-1}\)。基于平均年龄为\({\sim}20\) Myr 的 UCL、LCC 和 V1062 Sco 三个群的恒星，我们首次发现该恒星系统的体积膨胀系数与零显着不同，\ (K_{xyz}=43.2\pm 3.4\) km s \({}^{-1}\) kpc \({}^{-1}\)。