论文标题
在边缘的原星磁盘中追踪分子分层
Tracing Molecular Stratification within an Edge-on Protoplanetary Disk
论文作者
论文摘要
从分子物种发射中的Edge-On原始磁盘对不同临界密度和形成途径的分子物种发射中的高分辨率观察为追踪原动性磁盘的垂直化学和物理结构提供了机会。 Based on analysis of sub-arcsecond resolution Atacama Large Millimeter Array (ALMA) archival data for the edge-on Flying Saucer disk (2MASS J16281370-2431391), we establish the vertical and radial differentiation of the disk CN emitting regions with respect to those of $^{12}$CO and CS, and we model the disk physical conditions from which the CN emission arises.我们证明了磁盘$^{12} $ CO（2-1），CN（2-1）和CS J = 5-4发射区域的尺度高度高于中平面的高度下降，从而使12CO，CN和CS痕量沿较高的密度和降低的温度降低。我们发现，在中央恒星的半径> 100 au时，CN发射主要来自中间层，而在磁盘的内部区域，CN似乎是由更靠近中平面的层产生的。我们通过三种最亮的CN高精细系的Radex非LTE建模研究CN发射区域内的磁盘物理条件以及CN激发温度和色谱柱密度的范围。在磁盘中平面附近，我们在相对较低的t $ _ {kin} $（〜12 k）下得出密度NH2〜10 $^{7} $ cm $^{ - 3} $，我们发现CN被热降化，而在较高的（IntermedMedice）中似乎可以从较高的（Intermediper）中获得亚热的，非LTE的条件。我们考虑是否以及如何通过X射线和中央恒星的紫外磁盘的照射程度来控制飞碟中CN发射的特定空间位置和激发条件。
High-resolution observations of edge-on proto-planetary disks in emission from molecular species sampling different critical densities and formation pathways offer the opportunity to trace the vertical chemical and physical structures of protoplanetary disks. Based on analysis of sub-arcsecond resolution Atacama Large Millimeter Array (ALMA) archival data for the edge-on Flying Saucer disk (2MASS J16281370-2431391), we establish the vertical and radial differentiation of the disk CN emitting regions with respect to those of $^{12}$CO and CS, and we model the disk physical conditions from which the CN emission arises. We demonstrate that the disk $^{12}$CO (2-1), CN (2-1), and CS J=5-4 emitting regions decrease in scale height above the midplane, such that 12CO, CN, and CS trace layers of increasing density and decreasing temperature. We find that at radii > 100 au from the central star, CN emission arises predominantly from intermediate layers, while in the inner region of the disk, CN appears to arise from layers closer to the midplane. We investigate disk physical conditions within the CN emitting regions, as well as the ranges of CN excitation temperature and column density, via RADEX non-LTE modeling of the three brightest CN hyperfine lines. Near the disk midplane, where we derive densities nH2 ~10$^{7}$ cm$^{-3}$ at relatively low T$_{kin}$ (~12 K), we find that CN is thermalized, while sub-thermal, non-LTE conditions appear to obtain for CN emission from higher (intermediate) disk layers. We consider whether and how the particular spatial location and excitation conditions of CN emission from the Flying Saucer can be related to CN production that is governed, radially and vertically, by the degree of irradiation of the flared disk by X-rays and UV photons from the central star.
