论文标题
检测猎户座分子云中不规则的,亚MM不透明的结构:在形成的10000年内的质子?
Detection of Irregular, Sub-mm Opaque Structures in the Orion Molecular Clouds: Protostars within 10000 years of formation?
论文作者
论文摘要
我们报告了ALMA和VLA连续观测,这些观察结果可能会识别出猎户座分子云中四个最年轻的质体作为Orion Vandam计划的一部分。这些以0.87毫米和8毫米的亮,扩展,不规则发射的区别,在0.87 mm处光学厚度。这些结构与圆盘或点状形态不同,向其他猎户座质体构成。 0.87毫米的发射意味着温度为41-170 K,需要内部加热。明亮的8毫米发射意味着假设标准的灰尘不透明度模型,质量为0.5至1.2 m_sun。一个来源具有0类伴侣,而另一个来源表明子结构表明伴侣候选。检测到三个紧凑的外流,其中两个可能由同伴驱动,动态时间约为300至400年。最慢的流出可能由第一个静水压芯驱动。当塌陷碎片的中心在光学上厚到其自身的辐射时,这些质子似乎追踪了早期阶段,并且压缩会提高气体温度。该阶段被认为伴随着静液压核的形成。一个关键的问题是,这些结构是否在〜100年的自由秋季时间发展,还是在开尔文·赫尔姆霍兹(Kelvin-Helmholtz)时代发展了几千年。这些来源的数量意味着与开尔文 - 霍尔姆尔茨时间的终生约为6000年。在这种情况下,旋转和/或磁支持可能会减慢塌陷。
We report ALMA and VLA continuum observations that potentially identify the four youngest protostars in the Orion Molecular Clouds taken as part of the Orion VANDAM program. These are distinguished by bright, extended, irregular emission at 0.87 mm and 8 mm and are optically thick at 0.87 mm. These structures are distinct from the disk or point-like morphologies seen toward the other Orion protostars. The 0.87 mm emission implies temperatures of 41-170 K, requiring internal heating. The bright 8 mm emission implies masses of 0.5 to 1.2 M_sun assuming standard dust opacity models. One source has a Class 0 companion, while another exhibits substructure indicating a companion-candidate. Three compact outflows are detected, two of which may be driven by companions, with dynamical times of ~300 to ~400 years. The slowest outflow may be driven by a first hydrostatic core. These protostars appear to trace an early phase when the centers of collapsing fragments become optically thick to their own radiation and compression raises the gas temperature. This phase is thought to accompany the formation of hydrostatic cores. A key question is whether these structures are evolving on free fall times of ~100 years, or whether they are evolving on Kelvin-Helmholtz times of several thousand years. The number of these sources imply a lifetime of ~6000 years, in closer agreement with the Kelvin-Helmholtz time. In this case, rotational and/or magnetic support could be slowing the collapse.