The spatial evolution of young massive clusters II. Looking for imprints of star formation in NGC 2264 with Gaia DR2
The spatial evolution of young massive clusters II. Looking for imprints of star formation in NGC 2264 with Gaia DR2
复制标题
年轻大质量星团的空间演化II.
DOI：
10.1051/0004-6361/201936935
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发表时间：
2020
影响因子：
6.5
通讯作者：
Buckner A
中科院分区：
文献类型：
--
作者：
Buckner A
要更好地理解具有大质量恒星的星系团中恒星的形成，需要对恒星形成区域进行严格的动力学和空间分析。目的我们试图证明“INDIGN”是一个强大的空间分析工具，当与GaiaDR2的运动学数据相结合时，可以用来稳健地探索恒星形成的历史。方法我们利用GaiaDR2的自行数据和INDICATE数据比较了NGC 2264中不同演化阶段年轻恒星对象(YSO)的动态和空间分布。结果不同演化阶段YSO的动力学和空间行为是不同的。在动态上，II类YSO主要具有与已知子结构一致的非随机轨迹，而III类YSO具有随机轨迹，没有明显的扩张或收缩模式。在空间上，演化阶段与源浓度之间存在相关性：69.4%的0/I类物体、27.9%的II类物体和7.7%的III类物体聚集在一起。与同一类物体聚集在一起的YSO的比例也遵循了这一趋势。发现第0/I类物体与同一类的一般人口/物体的聚集度比第II类和第III类物体更紧密，分别为1.2/4.1和1.9/6.6倍。这些发现的一个例外是在S蒙的0.05°范围内，在那里III类天体模拟了更广泛的星系团区域内II类源的行为。我们的结果表明：(I)当前的YSOs分布是动力学演化的结果，(Ii)长时间的恒星形成是按顺序发生的，(Iii)来自S·蒙的恒星反馈使YSOs看起来是更进化的来源。结论旨在提供星团行为的定量测量的INDIT是进行严格空间分析的有力工具。我们的发现与关于NGC 2264的已知结果一致，有效地证明了当结合来自GaiaDR2的运动学数据时，可以用来以稳健的方式研究星系团的恒星形成历史。
ContextBetter understanding of star formation in clusters with high-mass stars requires rigorous dynamical and spatial analyses of star-forming regions.AimsWe seek to demonstrate that “INDICATE” is a powerful spatial analysis tool which when combined with kinematic data fromGaiaDR2 can be used to probe star formation history in a robust way.MethodsWe compared the dynamic and spatial distributions of young stellar objects (YSOs) at various evolutionary stages in NGC 2264 usingGaiaDR2 proper motion data and INDICATE.ResultsThe dynamic and spatial behaviours of YSOs at different evolutionary stages are distinct. Dynamically, Class II YSOs predominately have non-random trajectories that are consistent with known substructures, whereas Class III YSOs have random trajectories with no clear expansion or contraction patterns. Spatially, there is a correlation between the evolutionary stage and source concentration: 69.4% of Class 0/I, 27.9% of Class II, and 7.7% of Class III objects are found to be clustered. The proportion of YSOs clustered with objects of the same class also follows this trend. Class 0/I objects are both found to be more tightly clustered with the general populous/objects of the same class than Class IIs and IIIs by a factor of 1.2/4.1 and 1.9/6.6, respectively. An exception to these findings is within 0.05° of S Mon where Class III objects mimic the behaviours of Class II sources across the wider cluster region. Our results suggest (i) current YSOs distributions are a result of dynamical evolution, (ii) prolonged star formation has been occurring sequentially, and (iii) stellar feedback from S Mon is causing YSOs to appear as more evolved sources.ConclusionsDesigned to provide a quantitative measure of clustering behaviours, INDICATE is a powerful tool with which to perform rigorous spatial analyses. Our findings are consistent with what is known about NGC 2264, effectively demonstrating that when combined with kinematic data fromGaiaDR2 INDICATE can be used to study the star formation history of a cluster in a robust way.