A Tale of Two Transition Disks: ALMA Long-baseline Observations of ISO-Oph 2 Reveal Two Closely Packed Nonaxisymmetric Rings and a ∼2 au Cavity
A Tale of Two Transition Disks: ALMA Long-baseline Observations of ISO-Oph 2 Reveal Two Closely Packed Nonaxisymmetric Rings and a ∼2 au Cavity
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DOI：
10.3847/2041-8213/abbcce
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发表时间：
2020-10
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通讯作者：
Camilo Gonz'alez-Ruilova;L. Cieza;A. Hales;S. P'erez;A. Zurlo;C. Arce-Tord;S. Casassus;H. C'anovas-H.
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作者：
Camilo Gonz'alez-Ruilova;L. Cieza;A. Hales;S. P'erez;A. Zurlo;C. Arce-Tord;S. Casassus;H. C'anovas-H.
ISOPH2是一个宽间隔(240Au)的双星系统，其中主星有一个大质量(M Dust∼40M⊕)环状圆盘，半径为50Au的尘埃腔，而副星则有一个更轻的(M Dust∼0.8M∼)圆盘。作为Ophiuchus Disk Survey Using ALMA(ODISEA)项目的高分辨率后续工作的一部分，我们提供了该系统在002(3Au)分辨率下的1.3 mm连续谱和12co分子线观测。我们将主星周围的圆盘分解成两个非轴对称的环，发现次星周围的圆盘只有∼7Au横跨，并且还有一个尘埃空腔(r∼2.2Au)。根据系统的红外通量比和主星的M0光谱类型，我们估计伴星的质量接近棕矮星的极限。因此，我们得出结论：蛇夫座的ISO-Oph2系统包含最大和最小的空穴，最小的测量盘大小，以及蛇夫座中最小质量天体(M⋆∼0.08M⊙)周围的可分辨空穴。从12co的数据中，我们发现了连接两个磁盘的气桥。虽然围绕主星的环的形态可能是由于腔内看不见的干扰体造成的，但我们推测，这座桥可能表明了另一种情况，在这种情况下，副星最近经过了主星，导致了其圆盘的方位不对称。因此，ISO-Oph2系统是研究圆盘演化、行星形成和伴星-圆盘相互作用的卓越实验室。
ISO-Oph 2 is a wide-separation (240 au) binary system where the primary star harbors a massive (M dust ∼ 40 M ⊕) ring-like disk with a dust cavity ∼50 au in radius and the secondary hosts a much lighter (M dust ∼ 0.8 M ⊕) disk. As part of the high-resolution follow-up of the “Ophiuchus Disk Survey Employing ALMA” (ODISEA) project, we present 1.3 mm continuum and 12CO molecular line observations of the system at 002 (3 au) resolution. We resolve the disk around the primary into two nonaxisymmetric rings and find that the disk around the secondary is only ∼7 au across and also has a dust cavity (r ∼ 2.2 au). Based on the infrared flux ratio of the system and the M0 spectral type of the primary, we estimate the mass of the companion to be close to the brown-dwarf limit. Hence, we conclude that the ISO-Oph 2 system contains the largest and smallest cavities, the smallest measured disk size, and the resolved cavity around the lowest-mass object (M ⋆ ∼ 0.08 M ⊙) in Ophiuchus. From the 12CO data, we find a bridge of gas connecting both disks. While the morphology of the rings around the primary might be due to an unseen disturber within the cavity, we speculate that the bridge might indicate an alternative scenario in which the secondary has recently flown by the primary star causing the azimuthal asymmetries in its disk. The ISO-Oph 2 system is therefore a remarkable laboratory to study disk evolution, planet formation, and companion–disk interactions.