Stars with Photometrically Young Gaia Luminosities Around the Solar System (SPYGLASS). I. Mapping Young Stellar Structures and Their Star Formation Histories
Stars with Photometrically Young Gaia Luminosities Around the Solar System (SPYGLASS). I. Mapping Young Stellar Structures and Their Star Formation Histories
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DOI：
10.3847/1538-4357/ac0251
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发表时间：
2021-05
期刊：
影响因子：
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通讯作者：
R. Kerr;A. Rizzuto;A. Kraus;S. Offner
中科院分区：
文献类型：
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作者：
R. Kerr;A. Rizzuto;A. Kraus;S. Offner
年轻的恒星协会拥有可以持续数百万年的恒星形成记录，揭示了在出生云消散后很久恒星形成的进程。为了确定附近的年轻恒星群，我们设计了一个识别年轻恒星的综合框架，并利用盖亚DR2在333 pc的距离内识别了~ 3 × 104颗候选年轻恒星。将HDBSCAN聚类算法应用于该样本，我们确定了27个顶级组，其中近一半在以前的文献中几乎没有出现过。其中10个星团有可见的亚结构，包括著名的年轻星团，如猎户座、英仙座、金牛座和scoc - centn。我们提供了一个完整的亚聚类分析所有群体的亚结构，使用年龄估计来揭示每个区域的恒星形成历史。我们揭示的模式包括Sco-Cen沿半圆弧的明显恒星形成起源，以及以传播速度约4 km s - 1（约4 pc Myr - 1）的顺序恒星形成远离该弧的明确证据。我们还在英仙座和金牛座中发现了更早的恒星形成爆发，这些爆发早于当前的、运动学上相同的活跃恒星形成事件，这表明收集气体的机制可以激发多代恒星形成，其间穿插着气体分散和云的再生。我们观察恒星形成的大空间尺度和长时间尺度为单个分子云内部的过程和在星系尺度上指导恒星形成的广泛力量之间提供了一座桥梁。
Young stellar associations hold a star formation record that can persist for millions of years, revealing the progression of star formation long after the dispersal of the natal cloud. To identify nearby young stellar populations that trace this progression, we have designed a comprehensive framework for the identification of young stars and use it to identify ∼3 × 104 candidate young stars within a distance of 333 pc using Gaia DR2. Applying the HDBSCAN clustering algorithm to this sample, we identify 27 top-level groups, nearly half of which have little to no presence in previous literature. Ten of these groups have visible substructure, including notable young associations such as Orion, Perseus, Taurus, and Sco-Cen. We provide a complete subclustering analysis of all groups with substructure, using age estimates to reveal each region’s star formation history. The patterns we reveal include an apparent star formation origin for Sco-Cen along a semicircular arc, as well as clear evidence for sequential star formation moving away from that arc with a propagation speed of ∼4 km s−1 (∼4 pc Myr−1). We also identify earlier bursts of star formation in Perseus and Taurus that predate current, kinematically identical active star-forming events, suggesting that the mechanisms that collect gas can spark multiple generations of star formation, punctuated by gas dispersal and cloud regrowth. The large spatial scales and long temporal scales on which we observe star formation offer a bridge between the processes within individual molecular clouds and the broad forces guiding star formation at galactic scales.