论文标题
关于北天杆循环的起源
On the origin of the North Celestial Pole Loop
论文作者
论文摘要
北天极环（NCPL）为研究恒星形成的早期前体提供了独特的实验室。揭示其起源是理解控制其内容演变的动力学机制的关键。在这项研究中，我们分别使用高分辨率尘埃灭绝数据和H I数据探索了3D几何和NCPL的动力学。我们发现，朝向北极星和Ursa Major的材料沿着与Radcliffe波相似的平面分布。介于两者之间的蜘蛛似乎在3D中断开了连接，这是环形形状的不连续性。我们发现形成NCPL内部部分的细长腔是局部气泡（LB）的突出，可能充满了温暖（可能是热的）气体，这些气体经过并超出了密云的位置。一个理想化的腔体模型是针对观察者的岩体球体，让人联想到Meyerdierks等人提出的圆柱模型。 （1991年），涵盖了突出，并将其融合到温暖的气体的弧线中，向其横向膨胀。正如Meyerdierks等人首先争论的那样。 （1991年），腔的非球体几何形状以及它在其内部缺乏OB恒星的内部，不利于由单点样能源或多个超新星引起的起源。相反，突出的形成可能与下光环中的温暖气体从LB传播成一个先前存在的非均匀培养基有关，其拓扑可能是由沿当地手臂的过去星形地层活性塑造的。
The North Celestial Pole Loop (NCPL) provides a unique laboratory for studying the early stage precursors of star formation. Uncovering its origin is key to understanding the dynamical mechanisms that control the evolution of its contents. In this study, we explore the 3D geometry and the dynamics of the NCPL using high-resolution dust extinction data and H I data, respectively. We find that material toward Polaris and Ursa Major is distributed along a plane similarly oriented to the Radcliffe wave. The Spider projected in between appears disconnected in 3D, a discontinuity in the loop shape. We find that the elongated cavity that forms the inner part of the NCPL is a protrusion of the Local Bubble (LB) likely filled with warm (possibly hot) gas that passes through and goes beyond the location of the dense clouds. An idealized model of the cavity as a prolate spheroid oriented toward the observer, reminiscent of the cylindrical model proposed by Meyerdierks et al. (1991), encompasses the protrusion and fits into arcs of warm H I gas expanding laterally to it. As first argued by Meyerdierks et al. (1991), the non-spherical geometry of the cavity and the lack of OB stars interior to it disfavor an origin caused by a single point-like source of energy or multiple supernovae. Rather, the formation of the protrusion could be related to the propagation of warm gas from the LB into a pre-existing non-uniform medium in the lower halo, the topology of which was likely shaped by past star formation activity along the Local Arm.
