Abstract

Based on space velocity components UVW and using a recent dataset for Castor and Ursa Major moving groups, we compute the apex position with two methods. Classical convergent procedures give (A_cp, D_cp) = (80\(_{.}^{\circ}\)7830, –17\(_{.}^{\circ}\)2598; Castor, 298\(_{.}^{\circ}\)334, –34\(_{.}^{\circ}\)6405; UMa) for Castor and Ursa Major groups. According to the AD-map method we deduce the apex position (A₀, D₀) = (79\(_{.}^{\circ}\)5514, –17\(_{.}^{\circ}\)3948; Castor, 304\(_{.}^{\circ}\)767, ‒35\(_{.}^{\circ}\)2045; UMa) for these two objects. These results are in good agreement with other published coordinated. Also, we calculate all parameters with a model of stream velocity ellipsoidal motions, which reveals inner kinematical structure. Finally, we consider the intrinsic variations considered with late-type moving groups (streams) for the longitude of the vertex versus temperature (spectral types).

中文翻译：

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蓖麻和Ursa主要运动恒星群的顶点和运动结构

摘要

基于空间速度分量UVW并使用Castor和Ursa Major运动组的最新数据集，我们用两种方法计算顶点位置。经典收敛过程给出（A _cp，  D _cp）=（80 \（_ {。} ^ {\ circ} \） 7830，–17 \（__。^ {\ circ} \） 2598; Castor，298 \ （_ {。} ^ {\ circ} \） 334，–34 \（_ {。} ^ {\ circ} \） 6405； UMa）适用于Castor和Ursa Major组。根据AD-map方法，我们推导出顶点位置（A ₀，D ₀）=（79 \（_ {。} ^ {\ circ} \） 5514，–17 \（_ {。} ^ {\ circ} \） 3948； Castor，304 \（_ {。} ^ {\ circ} \） 767，‒35\（_ {。} ^ {\ circ} \） 2045; 这两个对象。这些结果与其他已发布的协调一致。此外，我们使用流速度椭球运动模型计算所有参数，从而揭示内部运动学结构。最终，我们考虑了与后期类型的移动组（流）有关的顶点经度与温度（频谱类型）的内在变化。