First Subarcsecond Submillimeter-wave [C i] Image of 49 Ceti with ALMA
First Subarcsecond Submillimeter-wave [C i] Image of 49 Ceti with ALMA
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DOI：
10.3847/1538-4357/ab3d26
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发表时间：
2019-08
期刊：
影响因子：
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通讯作者：
A. Higuchi;K. Saigo;H. Kobayashi;K. Iwasaki;M. Momose;Kang Lou Soon;N. Sakai;M. Kunitomo;
中科院分区：
文献类型：
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作者：
A. Higuchi;K. Saigo;H. Kobayashi;K. Iwasaki;M. Momose;Kang Lou Soon;N. Sakai;M. Kunitomo;
我们给出了用阿塔卡马大毫米/亚毫米阵列观测到的49个CETI在[CI]3P1-3P0发射和614μm尘埃连续发射中的第一幅亚弧秒图像，以及利用该阵列记录的CO(J=3-2)发射的图像。614μm尘埃连续发射的空间分布是围绕中心星的半径约为100Au的宽环结构。大量的气体也与49个Ceti有关。[CI]发射图显示尘环内有两个峰值，其总体幅度与尘埃连续排放和CO排放相当。我们发现[CI]/CO(J=3-2)强度比沿长轴有明显的变化。该比值在粉尘峰值位置附近取最小值1.8，并由内向外逐渐增大。中央恒星(∼3)周围的增强率可能来自恒星的紫外线辐射，而外盘(∼10)的增强率可能来自星际紫外线辐射。这种[CI]和CO(J=3-2)排放的复杂分布将是理解49CETI气体来源的关键，也将对气态碎片盘的物理和化学模型提供严格的约束。
We present the first subarcsecond images of 49 Ceti in the [C i] 3P1–3P0 emission and the 614 μm dust continuum emission observed with Atacama Large Millimeter/submillimeter Array (ALMA), as well as that in the CO(J = 3–2) emission prepared by using the ALMA archival data. The spatial distribution of the 614 μm dust continuum emission is found to have a broad-ring structure with a radius of about 100 au around the central star. A substantial amount of gas is also associated with 49 Ceti. The [C i] emission map shows two peaks inside the dust ring, and its overall extent is comparable to that of the dust continuum emission and the CO emission. We find that the [C i]/CO(J = 3–2) intensity ratio significantly varies along the major axis. The ratio takes the minimum value of 1.8 around the dust peak position, and increases inward and outward. The enhanced ratio around the central star (∼3) likely originates from the stellar UV radiation, while that in the outer disk (∼10) is from the interstellar UV radiation. Such complex distributions of the [C i] and CO(J = 3–2) emission will be key to understanding the origin of the gas in 49 Ceti, and will also provide a stringent constraint on physical and chemical models of gaseous debris disks.