标题： 集群对 SL 538/ NGC 2006 (SL 537) 显示英文标题

标题： The cluster pair SL 538/ NGC 2006 (SL 537)

摘要： 我们详细研究了大麦哲伦星云（LMC）中的两个双星团候选体SL 538和NGC 2006。 这一星团对位于超大壳状结构LMC 4中大型OB星协LH 77的西北部。 第三个星团KMHK 1019位于该星团对5'范围内。 我们的研究是首次基于CMDs对SL 538和NGC 2006的年龄测定。 我们得出SL 538的年龄为18+/-2 Myr，NGC 2006的年龄为22.5+/-2.5 Myr，KMHK 1019的年龄为16 Myr。 因此这三个星团几乎是同时形成的。 我们识别出Be星候选体，并发现双星团组分中的N(Be)/N(B)比率相同（12%），而KMHK 1019中检测到的Be星数量（5%）以及周围区域（2%）的数量明显较低。 由于Be星通常是快速旋转体，这可能表明该星团对的组分具有固有的较高旋转速度。 此外，从CMDs导出的IMF显示SL 538和NGC 2006具有相同的斜率，并且与Salpeter IMF一致。 基于IMF斜率对星团质量的估计表明，这两个星团具有相似的总质量。 这些发现支持该星团对在同一巨分子云中近同时形成。 显示英文摘要

摘要： We studied in detail the binary cluster candidates SL 538 and NGC 2006 in the Large Magellanic Cloud (LMC). This cluster pair is located in the northwestern part of the large OB association LH 77 in supergiant shell LMC 4. A third star cluster, KMHK 1019, is located within 5' from the cluster pair. Our study is the first age determination of SL 538 and NGC 2006 that is based on CMDs. We derived an age of 18+/-2 Myr for SL 538, 22.5+/-2.5 Myr for NGC 2006, and 16 Myr for KMHK 1019. Thus the three clusters are (nearly) coeval. We identified Be star candidates and find the same ratio N(Be)/N(B) for the components of the binary cluster (12%) while the amount of Be stars detected in KMHK 1019 (5%) and in the surrounding field (2%) is considerably lower. Since Be stars are usually rapid rotators this may indicate intrinsically higher rotational velocities in the components of the cluster pair. Also the IMF derived from the CMDs shows the same slope for both SL 538 and NGC 2006 and is consistent with a Salpeter IMF. An estimation of the cluster masses based on the IMF slopes showed that both clusters have similar total masses. These findings support joint, near-simultaneous formation of the cluster pair in the same giant molecular cloud.