arXivDaily arXiv每日学术速递 周一至周五更新
北美退伍军人节（Veterans Day），12 日无更新
arXiv 2010.02249astro-ph.EPastro-ph.GA
收藏

原行星盘的多波长连续谱尺寸：颗粒生长和径向漂移的标度关系和意义

Multi-wavelength continuum sizes of protoplanetary discs: scaling relations and implications for grain growth and radial drift

Marco Tazzari, Cathie J. Clarke, Leonardo Testi, Jonathan P. Williams, Stefano Facchini, Carlo F. Manara, Antonella Natta, Giovanni Rosotti

备注：
MNRAS Accepted. 20 pages, 12 figures, 5 tables. Detailed fit results in Appendix E (27 pages, 78 figures), available as supplementary material. Machine-readable version of Table 1, Table 2, and Table 3 available at https://zenodo.org/record/4756381
阅读 PDF
arXiv 页面 ↗HTML 原文 ↗

摘要：

我们分析空间分辨ALMA观测在0.9，1.3，和3.1毫米的26个最明亮的原行星盘在狼疮恒星形成区域。我们通过以均匀的方式拟合干涉仪的亮度分布，获得在三个波长处的有效盘尺寸，光谱指数分布和光学深度估计，从而获得盘的多波长亮度分布。我们报告了三个基本发现：首先，在0.9 mm处已经观察到的毫米连续体尺寸-光度关系在1.3 mm处也存在相同的斜率，并且在3.1 mm处具有更陡的斜率，这证实了在较长波长处的发射变得越来越光学薄。第二，当在3.1毫米处观察时，圆盘似乎只比在0.9毫米处观察时小9%，与预测更明显差异的尘埃演化模型相矛盾。第三，通过一个简单的参数光盘模型的测量样品的正向建模，我们发现，整个光盘的大颗粒（$a_\mathrm{max}>1 $ mm）的存在是最有利的解释，所有光盘，因为它同时再现其光谱指数，光学深度，光度，和径向范围在0.9-1.3毫米波长范围。我们还发现，观测结果可以交替解释与光盘被占主导地位的光学厚，未解决的，子结构制成的毫米大小的颗粒具有高散射的散射。

英文摘要：

We analyse spatially resolved ALMA observations at 0.9, 1.3, and 3.1 mm for the 26 brightest protoplanetary discs in the Lupus star-forming region. We characterise the discs multi-wavelength brightness profiles by fitting the interferometric visibilities in a homogeneous way, obtaining effective disc sizes at the three wavelengths, spectral index profiles and optical depth estimates. We report three fundamental discoveries: first, the millimeter continuum size - luminosity relation already observed at 0.9 mm is also present at 1.3 mm with an identical slope, and at 3.1 mm with a steeper slope, confirming that emission at longer wavelengths becomes increasingly optically thin. Second, when observed at 3.1 mm the discs appear to be only 9% smaller than when observed at 0.9 mm, in tension with models of dust evolution which predict a starker difference. Third, by forward modelling the sample of measurements with a simple parametric disc model, we find that the presence of large grains ($a_\mathrm{max}>1 $mm) throughout the discs is the most favoured explanation for all discs as it reproduces simultaneously their spectral indices, optical depth, luminosity, and radial extent in the 0.9-1.3 mm wavelength range. We also find that the observations can be alternatively interpreted with the discs being dominated by optically thick, unresolved, substructures made of mm-sized grains with a high scattering albedo.

机构、总结、中文摘要均由AI分析而来，可能存在错误，请以论文正文为准。

↑