论文标题
彗星云LDN 1616中的磁场和年轻恒星物体
Magnetic fields and young stellar objects in cometary cloud LDN 1616
论文作者
论文摘要
LDN 1615/1616和CB 28(以下称为L1616)一起形成一个彗星球,位于Orion OB1关联以西约8度的角度距离,沿着东西方向大致对齐,并显示出独特的头尾结构。猎户座带中的大恒星的存在被认为是L1616中恒星形成的辐射驱动的内爆模式的原因。基于与L1616相关的先前已知的年轻恒星对象(YSO)的最新Gaia EDR3测量值,我们找到了与384美元$ \ pm $ 5 PC的云的距离。我们向L1616提出光学极化法,该光仪映射了环境磁场(b $ _ {pos} $)几何形状的天平成分。基于与L1616相关的YSO的适当运动,我们研究了它们相对于令人兴奋的恒星$ε$ ORI的天际飞机运动。使用YSO的距离和适当运动的Gaia EDR3测量值,我们发现了两个与已知YSO的其他来源。一个共同的来源是HD33056,是B9恒星,另一个可能是先前研究中未报告的年轻预选前序列。 b $ _ {pos} $的平均方向遵循云结构。这可能是通过$ε$ ori的电离辐射的影响来拖动磁场线的效果。基于在L1616上施加的压力以及相关YSO的年龄,我们表明它可能是L1616中电离的主要来源,因此可能是其中的恒星形成。
LDN 1615/1616 and CB 28 (hereafter, L1616) together form a cometary globule located at an angular distance of about 8 degrees west of the Orion OB1 association, aligned roughly along the east-west direction, and showing a distinct head-tail structure. The presence of massive stars in the Orion belt has been considered to be responsible for the radiation driven implosion mode of star formation in L1616. Based on the latest Gaia EDR3 measurements of the previously known young stellar objects (YSOs) associated with L1616, we find the distance to this cloud of 384$\pm$5 pc. We present optical polarimetry towards L1616 that maps the plane-of-sky component of the ambient magnetic field (B$_{POS}$) geometry. Based on the proper motion of the YSOs associated with L1616, we investigate their plane-of-sky motion relative to the exciting star $ε$ Ori. Using the Gaia EDR3 measurements of the distances and proper motions of the YSOs, we find two additional sources comoving with the known YSOs. One comoving source is HD33056, a B9 star and the other might be a young pre-main sequence star not reported in previous studies. The mean direction of B$_{POS}$ is found to follow the cloud structure. This could be the effect of dragging of the magnetic field lines by the impact of the ionizing radiation from $ε$ Ori. Based on the pressure exerted on L1616, and the ages of the associated YSOs, we show that it could possibly be the main source of ionization in L1616, and thus the star formation in it.