Additional TWA Members? Spectroscopic verification of kinematically selected TWA candidates
Additional TWA Members? Spectroscopic verification of kinematically selected TWA candidates
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其他环球航空会员？
DOI：
10.1051/0004-6361:20020159
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发表时间：
2002
影响因子：
6.5
通讯作者：
B. Zuckerman
中科院分区：
文献类型：
--
作者：
I. Song;M. Bessell;B. Zuckerman
我们提供了来自Makarov和Fabricius（2001）的TW Hydrae协会的23个新候选成员的光谱测量结果。基于H和Li 6708 A的强度以及依巴谷TWA候选者的颜色-星等图上的位置，除了已知的成员TWA 19之外，我们只发现了三个可能的新成员（TYC 7760-0835- 1，TYC 8238-1462-1和TYC 8234-2856-1）。这就排除了大多数距离超过100 pc的候选人。三颗第谷星，几乎可以肯定是下半人马座十字星的成员，是TWA中最遥远的成员。根据我们的新结果，必须重新评估TWA各向同性膨胀的主张。一般来说，人们不能仅仅根据运动学数据来识别一个离我们很近的恒星群的新成员。为了消除具有相似运动学的闯入者，光谱验证是必不可少的。
We present spectroscopic measurements of the 23 new candidate members of the TW Hydrae Association from Makarov & Fabricius (2001). Based on H and Li 6708 A strengths together with location on a color- magnitude diagram for Hipparcos TWA candidates, we found only three possible new members (TYC 7760-0835- 1, TYC 8238-1462-1, and TYC 8234-2856-1) in addition to the already known member, TWA 19. This eliminated most of the candidates more distant than 100 pc. Three Tycho stars, almost certainly members of the Lower Centaurus Crux association, are the most distant members of the TWA. A claim of isotropic expansion of TWA has to be re-evaluated based on our new results. Generally, one cannot identify new members of a diuse nearby stellar group based solely on kinematic data. To eliminate interlopers with similar kinematics, spectroscopic verication is essential.