A Dust Trap in the Young Multiple System HD 34700
A Dust Trap in the Young Multiple System HD 34700
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DOI：
10.3847/1538-4357/abc74b
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发表时间：
2020-11
期刊：
影响因子：
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通讯作者：
P. Benac;L. Matrà;D. Wilner;M. Jiménez-Donaire;J. Monnier;T. Harries;A. Laws;Evan A. Rich;
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文献类型：
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作者：
P. Benac;L. Matrà;D. Wilner;M. Jiménez-Donaire;J. Monnier;T. Harries;A. Laws;Evan A. Rich;
对年轻恒星周围盘的毫米观测揭示了指示气体压力陷阱的子结构，这可能有助于颗粒生长和行星形成。我们提出了HD 34700的亚毫米阵列观测：两个Herbig Ae星在一个紧密的二元系统（Aa/Ab，Au 0.25），由一个磁盘呈现一个大的空腔和螺旋臂散射光，和两个遥远的，低质量的同伴包围。这些观测包括1.3 mm连续谱发射和分辨率为178 Au的~（12）CO 2-1谱线。他们解决了一个突出的方位角不对称的连续和开普勒旋转的circumbinary磁盘中的12 CO线。不对称性位于半径155+11 −7 Au处，与散射光腔的边缘一致，在半径（72 + 14 −15 Au）和方位角（FWHM = 64°+8 −7）上都可以分辨。毫米连续辐射的强烈不对称性可能是尘埃陷阱的证据，以及更对称的12 CO发射和小颗粒的形态。我们假设一个看不见的环双星的同伴负责在散射光腔，并在腔的边缘，在尘埃捕获表现出一个漩涡。由于探测到12 CO和未探测到13 CO，盘质量受到限制。我们讨论了它的潜在的过去这个系统的引力不稳定性的后果，可能占快速形成的一个circumbinary同伴。我们还报告了与HD 34700 B（预计分离Au 1850），我们解释通过拱盘解决连续发射的发现。
Millimeter observations of disks around young stars reveal substructures indicative of gas pressure traps that may aid grain growth and planet formation. We present Submillimeter Array observations of HD 34700: two Herbig Ae stars in a close binary system (Aa/Ab, ∼0.25 au), surrounded by a disk presenting a large cavity and spiral arms seen in scattered light, and two distant, lower-mass companions. These observations include 1.3 mm continuum emission and the 12CO 2–1 line at ∼05 (178 au) resolution. They resolve a prominent azimuthal asymmetry in the continuum and Keplerian rotation of a circumbinary disk in the 12CO line. The asymmetry is located at a radius of 155+11 −7 au, consistent with the edge of the scattered-light cavity, being resolved in both radius (72 +14 −15 au) and azimuth (FWHM = 64°+8 −7). The strong asymmetry in millimeter continuum emission could be evidence for a dust trap, together with the more symmetric morphology of 12CO emission and small grains. We hypothesize an unseen circumbinary companion responsible for the cavity in scattered light and creating a vortex at the cavity edge that manifests in dust trapping. The disk mass has limitations imposed by the detection of 12CO and nondetection of 13CO. We discuss its consequences for the potential past gravitational instability of this system, likely accounting for the rapid formation of a circumbinary companion. We also report the discovery of resolved continuum emission associated with HD 34700B (projected separation ∼1850 au), which we explain through a circumstellar disk.