Annular substructures in the transition disks around LkCa 15 and J1610
Annular substructures in the transition disks around LkCa 15 and J1610
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DOI：
10.1051/0004-6361/202038027
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发表时间：
2020-05
期刊：
影响因子：
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通讯作者：
S. Facchini;M. Benisty;J. Bae;R. Loomis;L. M. Pérez;M. Ansdell;S. Mayama;Paola Pinilla;
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作者：
S. Facchini;M. Benisty;J. Bae;R. Loomis;L. M. Pérez;M. Ansdell;S. Mayama;Paola Pinilla;
我们提出了高分辨率毫米连续阿尔马观测的磁盘周围的金牛座T星LkCa 15和J1610。这些磁盘托管尘埃耗尽的内部区域，可能是由大质量行星雕刻的，并且是研究行星-磁盘相互作用的印记的主要兴趣。在中等角分辨率下，它们看起来像是一个围绕着空腔的宽环，而连续辐射在~ 60 × 40质量的分辨率下分解成多个环（LkCa 15的~7.5 Au，J1610的~6 Au）和1.3 mm处的~ 7\，\mu $Jy光束$^{-1}$ rms。除了宽的扩展组件外，LkCa 15和J1610分别拥有3个和2个窄环，LkCa 15中有两个明亮的环被径向分辨。环看起来稍微光学厚，峰值光学深度约为0.5（忽略散射），与高角分辨率观测的完整磁盘一致。我们进行流体动力学模拟与嵌入式，亚木星质量的行星，并表明所观察到的多环子结构可以定性地解释为行星盘相互作用的结果。然而，我们注意到，单独选择磁盘冷却时间尺度可以显着影响行星周围的气体和尘埃分布，导致不同数量的环和间隙以及它们之间的不同间距。我们认为过渡盘的大质量外盘区域是星子和可能的第二代行星形成的有利场所，这些行星的质量低于雕刻内腔的行星（通常只有几个M_{\rm Jup}$），并且在LkCa 15和J1610中观察到的环形子结构可能表明富含尘埃的压力陷阱内的行星核心形成。目前的观察是兼容的其他机制是在所观察到的子结构的起源，特别是在CO和N$_2$雪线的边缘产生的窄环。
We present high resolution millimeter continuum ALMA observations of the disks around the T Tauri stars LkCa 15 and J1610. These disks host dust-depleted inner regions, possibly carved by massive planets, and are of prime interest to study the imprints of planet-disk interactions. While at moderate angular resolution they appear as a broad ring surrounding a cavity, the continuum emission resolves into multiple rings at a resolution of ~60$\times$40 mas (~7.5 au for LkCa 15, ~6 au for J1610) and ~$7\,\mu$Jy beam$^{-1}$ rms at 1.3 mm. In addition to a broad extended component, LkCa 15 and J1610 host 3 and 2 narrow rings, respectively, with two bright rings in LkCa 15 being radially resolved. The rings look marginally optically thick, with peak optical depths of ~0.5 (neglecting scattering), in agreement with high angular resolution observations of full disks. We perform hydrodynamical simulations with an embedded, sub-Jovian-mass planet and show that the observed multi-ringed substructure can be qualitatively explained as the outcome of the planet-disk interaction. We note however that the choice of the disk cooling timescale alone can significantly impact the resulting gas and dust distributions around the planet, leading to different numbers of rings and gaps and different spacings between them. We propose that the massive outer disk regions of transition disks are favorable places for planetesimals and possibly second generation planet formation of objects with a lower mass than the planets carving the inner cavity (typically few $M_{\rm Jup}$), and that the annular substructures observed in LkCa 15 and J1610 may be indicative of planetary core formation within dust-rich pressure traps. Current observations are compatible with other mechanisms being at the origin of the observed substructures, in particular with narrow rings generated at the edge of the CO and N$_2$ snowlines.