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arXiv 0906.0730astro-ph.EPastro-ph.SR
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蛇夫座的原行星盘结构

Protoplanetary Disk Structures in Ophiuchus

Sean M. Andrews, D. J. Wilner, A. M. Hughes, Chunhua Qi, C. P. Dullemond

摘要:

我们提出了一个高角分辨率(0.3”= 40 AU)的SMA调查的870微米的热连续辐射从9个最明亮的,因此最大的质量,拱星盘在~1万年的蛇夫座恒星形成区域。使用2-D辐射转移计算,我们同时拟合观察到的连续光谱和宽带光谱能量分布的每个磁盘的参数结构模型。与以前的毫米研究相比,这次调查包括建模,数据质量和角分辨率的显着升级,提供了改进的关键结构参数的约束,特别是那些表征磁盘中质量的空间分布。在由粘性吸积盘的相似解激发的表面密度分布的背景下,样品盘的最佳拟合模型具有特征半径Rc = 20-200 AU,高盘质量M_d = 0.005-0.14 M_sun,以及围绕中值$γ$ = 0.9的窄范围的径向表面密度梯度。这些密度结构与文献中的吸积率估计一起使用,以帮助表征盘材料的粘性演化。使用盘粘度的标准处方,这些组合约束表明$α$ = 0.0005-0.08。三个样品磁盘显示大(R = 20-40 AU)的连续发射形态的中心空腔,标记广泛的区域,其中灰尘已被物理删除和/或显着减少不透明度。根据目前行星形成模型的要求,这些发射空腔和样品的结构限制表明,这些年轻的磁盘可能最终产生行星系,也许已经开始。(节略)

英文摘要:

We present a high angular resolution (0.3" = 40 AU) SMA survey of the 870 micron thermal continuum emission from 9 of the brightest, and therefore most massive, circumstellar disks in the ~1 Myr-old Ophiuchus star-forming region. Using 2-D radiative transfer calculations, we simultaneously fit the observed continuum visibilities and broadband spectral energy distribution for each disk with a parametric structure model. Compared to previous millimeter studies, this survey includes significant upgrades in modeling, data quality, and angular resolution that provide improved constraints on key structure parameters, particularly those that characterize the spatial distribution of mass in the disks. In the context of a surface density profile motivated by similarity solutions for viscous accretion disks, the best-fit models for the sample disks have characteristic radii R_c = 20-200 AU, high disk masses M_d = 0.005-0.14 M_sun, and a narrow range of radial surface density gradients around a median $γ$ = 0.9. These density structures are used in conjunction with accretion rate estimates from the literature to help characterize the viscous evolution of the disk material. Using the standard prescription for disk viscosities, those combined constraints indicate that $α$ = 0.0005-0.08. Three of the sample disks show large (R = 20-40 AU) central cavities in their continuum emission morphologies, marking extensive zones where dust has been physically removed and/or has significantly diminished opacities. Based on the current requirements of planet formation models, these emission cavities and the structure constraints for the sample as a whole suggest that these young disks may eventually produce planetary systems, and have perhaps already started. (abridged)

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