ALMA Detection of Extended Millimeter Halos in the HD 32297 and HD 61005 Debris Disks
ALMA Detection of Extended Millimeter Halos in the HD 32297 and HD 61005 Debris Disks
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DOI：
10.3847/1538-4357/aaec71
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发表时间：
2018-12
期刊：
影响因子：
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通讯作者：
M. MacGregor;A. Weinberger;A. Hughes;D. Wilner;T. Currie;J. Debes;J. Donaldson;S. Red;
中科院分区：
文献类型：
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作者：
M. MacGregor;A. Weinberger;A. Hughes;D. Wilner;T. Currie;J. Debes;J. Donaldson;S. Red;
我们展示了阿塔卡马大型毫米/亚毫米阵列 (ALMA) 1.3 毫米 (230 GHz) 对 HD 32297 和 HD 61005 碎片盘的观测结果，这两个碎片盘是最具标志性的碎片盘，因为它们在散射光图像中看到了引人注目的后掠翼。这些观测结果使 HD 32297 和 HD 61005 的灵敏度分别达到 14 和 13 μJy beam−1，并提供了这两个系统迄今为止在毫米波长下的最高分辨率图像。通过采用马尔可夫链蒙特卡罗建模方法，我们确定这两个圆盘最好用双分量模型来描述，该模型由宽（ΔR/R > 0.4）的星子带组成，表面密度梯度上升，外晕与散射光圆盘对齐急剧下降。 HD 32297的星子带内缘和外缘位于78.5±8.1个天文单位和122±3个天文单位，HD 61005的星子带内缘和外缘位于41.9±0.9个天文单位和67.0±0.5个天文单位。晕分别延伸到440±32个天文单位和188±8个天文单位。我们还检测到与灰尘连续体位于同一位置的 HD 32297 的 12CO J = 2–1 气体排放。这些新的 ALMA 图像提供了观测证据，表明较大的毫米级颗粒也可能填充在这两个圆盘的扩展光晕中，而此前人们认为这两个圆盘仅由微米级的小颗粒组成。我们讨论了这些结果对不对称碎片盘的潜在塑造和雕刻机制的影响。
We present Atacama Large Millimeter/submillimeter Array (ALMA) 1.3 mm (230 GHz) observations of the HD 32297 and HD 61005 debris disks, two of the most iconic debris disks because of their dramatic swept-back wings seen in scattered light images. These observations achieve sensitivities of 14 and 13 μJy beam−1 for HD 32297 and HD 61005, respectively, and provide the highest resolution images of these two systems at millimeter wavelengths to date. By adopting a Markov Chain Monte Carlo modeling approach, we determine that both disks are best described by a two-component model consisting of a broad (ΔR/R > 0.4) planetesimal belt with a rising surface density gradient and a steeply falling outer halo aligned with the scattered light disk. The inner and outer edges of the planetesimal belt are located at 78.5 ± 8.1 au and 122 ± 3 au for HD 32297, and 41.9 ± 0.9 au and 67.0 ± 0.5 au for HD 61005. The halos extend to 440 ± 32 au and 188 ± 8 au, respectively. We also detect 12CO J = 2–1 gas emission from HD 32297 co-located with the dust continuum. These new ALMA images provide observational evidence that larger, millimeter-sized grains may also populate the extended halos of these two disks previously thought to only be composed of small, micron-sized grains. We discuss the implications of these results for potential shaping and sculpting mechanisms of asymmetric debris disks.