We derive the distance and structure of the Perseus molecular cloud by combining trigonometric parallaxes from Very Long Baseline Array (VLBA) observations, taken as part of the GOBELINS survey and Gaia Data Release 2. Based on our VLBA astrometry, we obtain a distance of 321?±?10?pc for IC?348. This is fully consistent with the mean distance of 320?±?26 measured by Gaia. The VLBA observations toward NGC?1333 are insufficient to claim a successful distance measurement to this cluster. Gaia parallaxes, on the other hand, yield a mean distance of 293?±?22?pc. Hence, the distance along the line of sight between the eastern and western edges of the cloud is ~30?pc, which is significantly smaller than previously inferred. We use Gaia proper motions and published radial velocities to derive the spatial velocities of a selected sample of stars. The average velocity vectors with respect to the LSR are = (?6.1 ± 1.6, 6.8 ± 1.1, ?0.9 ± 1.2) and (?6.4 ± 1.0, 2.1 ± 1.4, ?2.4 ± 1.0) km s?1 for IC?348 and NGC?1333, respectively. Finally, our analysis of the kinematics of the stars has shown that there is no clear evidence of expansion, contraction, or rotational motions within the clusters.
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机译：我们通过结合极长基线阵列（VLBA）观测值中的三角视差，得出珀尔修斯分子云的距离和结构，这些观测值是GOBELINS调查和Gaia Data Release 2的一部分。基于VLBA天体测量，我们得出了321的距离IC±348的±±10pc这与盖亚（Gaia）测得的平均距离320？±？26完全一致。对NGC？1333的VLBA观测结果不足以要求对该簇成功进行距离测量。另一方面，盖亚视差产生的平均距离为293°±22°pc。因此，沿云的东西边缘之间的视线距离约为30？pc，这比以前推断的要小得多。我们使用盖亚（Gaia）适当运动和已发布的径向速度来导出选定恒星样本的空间速度。相对于LSR的平均速度矢量为IC？348 =（？6.1±1.6，6.8±1.1，？0.9±1.2）和（？6.4±1.0，2.1±1.4，？2.4±1.0）km s？1和NGC？1333。最后，我们对恒星运动学的分析表明，没有清晰的证据表明星团内有膨胀，收缩或旋转运动。
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