Four annular structures in a protostellar disk less than 500,000 years old
Four annular structures in a protostellar disk less than 500,000 years old
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DOI：
10.1038/s41586-020-2779-6
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发表时间：
2020-10
期刊：
影响因子：
64.8
通讯作者：
D. Segura-Cox;A. Schmiedeke;J. Pineda;I. Stephens;M. Fern'andez-L'opez;L. Looney;P. Caselli;
中科院分区：
文献类型：
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作者：
D. Segura-Cox;A. Schmiedeke;J. Pineda;I. Stephens;M. Fern'andez-L'opez;L. Looney;P. Caselli;
在主序前恒星周围的星盘中，已经发现了大量的环形结构（环和间隙），这些结构存在于大约100万年前的II类原恒星物体中。这些结构通常被解释为行星形成的证据，-，行星质量的物体在圆盘上雕刻环和间隙。这意味着行星的形成可能已经在I类阶段的更年轻的盘中进行，当时原恒星仍然嵌入在更大规模的致密气体和尘埃包层中。只有在过去的十年中，才能观察到最早恒星形成阶段的盘的详细特性。在这里，我们报告了1.3毫米的尘埃排放观测，分辨率为5个天文单位，显示了年轻（不到50万年）的原恒星IRS 63的圆盘中的四个环形子结构。IRS 63是一个位于蛇夫座分子云附近的单一I类源，距离144秒差距，是毫米波长最亮的I类原恒星之一。IRS 63也有一个相对于其他年轻的磁盘（大于50天文单位）较大的磁盘。在年轻时观察到的多个环形子结构可以作为尘埃颗粒生长的早期立足点，这是行星形成的先决条件。无论IRS 63的星盘中是否已经存在行星，很明显，行星形成过程开始于最初的原恒星阶段，比目前行星形成理论预测的要早。
Annular structures (rings and gaps) in disks around pre-main-sequence stars have been detected in abundance towards class II protostellar objects that are approximately 1,000,000 years old. These structures are often interpreted as evidence of planet formation, –, with planetary-mass bodies carving rings and gaps in the disk. This implies that planet formation may already be underway in even younger disks in the class I phase, when the protostar is still embedded in a larger-scale dense envelope of gas and dust. Only within the past decade have detailed properties of disks in the earliest star-forming phases been observed,. Here we report 1.3-millimetre dust emission observations with a resolution of five astronomical units that show four annular substructures in the disk of the young (less than 500,000 years old) protostar IRS 63. IRS 63 is a single class I source located in the nearby Ophiuchus molecular cloud at a distance of 144 parsecs, and is one of the brightest class I protostars at millimetre wavelengths. IRS 63 also has a relatively large disk compared to other young disks (greater than 50 astronomical units). Multiple annular substructures observed towards disks at young ages can act as an early foothold for dust-grain growth, which is a prerequisite of planet formation. Whether or not planets already exist in the disk of IRS 63, it is clear that the planet-formation process begins in the initial protostellar phases, earlier than predicted by current planet-formation theories.