Probing Signatures of a Distant Planet around the Young T-Tauri Star CI Tau Hosting a Possible Hot Jupiter
Probing Signatures of a Distant Planet around the Young T-Tauri Star CI Tau Hosting a Possible Hot Jupiter
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DOI：
10.3847/2041-8213/aac6d2
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发表时间：
2018-05
期刊：
影响因子：
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通讯作者：
M. Konishi;J. Hashimoto;Y. Hori
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文献类型：
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作者：
M. Konishi;J. Hashimoto;Y. Hori
我们在 200 万年前的经典 T-Tauri 恒星 CI Tau 周围寻找一颗遥远行星的特征，该恒星在偏心轨道 (e ∼ 0.3) 上托管着一颗热木星候选者 ( )。为了探测外部扰动因素的存在，我们重新分析了由阿塔卡马大型毫米/亚毫米阵列（ALMA）获得的 CI Tau 周围原行星盘的 1.3 毫米尘埃连续观测数据。我们在 CI Tau 圆盘中~0.″8 处发现了一个间隙结构。我们的可见度拟合假设轴对称表面亮度分布表明间隙位于 104.5 ± 1.6 au 的投影半径处，宽度为 36.9 ± 2.9 au。经计算，间隙周围的亮度温度比周围圆盘的亮度温度低约 2.3 K。长期引力不稳定性 (GI) 和灰尘捕获等间隙打开机制可以解释 CI Tau 盘中的间隙形态。不能排除一颗看不见的行星创造了观测到的间隙结构的可能性，尽管偏心的热木星和年轻 CI Tau 周围的遥远行星的共存对于引力散射场景来说是一个挑战。根据模型表面亮度图像中的间隙宽度和深度（ ），估计该行星的质量在 ~0.25 MJupiter 和 ~0.8 MJupiter 之间，低于当前高对比度直接成像的检测极限。年轻的经典T-Tauri CI Tau可能是一个独特的系统，用于探索潜在的遥远行星的存在以及古怪的热木星的起源。
We search for signatures of a distant planet around the two million-year-old classical T-Tauri star CI Tau hosting a hot-Jupiter candidate ( ) in an eccentric orbit (e ∼ 0.3). To probe the existence of an outer perturber, we reanalyzed 1.3 mm dust continuum observations of the protoplanetary disk around CI Tau obtained by the Atacama Large Millimeter/submillimeter Array (ALMA). We found a gap structure at ∼0.″8 in CI Tau’s disk. Our visibility fitting assuming an axisymmetric surface brightness profile suggested that the gap is located at a deprojected radius of 104.5 ± 1.6 au and has a width of 36.9 ± 2.9 au. The brightness temperature around the gap was calculated to be ∼2.3 K lower than that of the ambient disk. Gap-opening mechanisms such as secular gravitational instability (GI) and dust trapping can explain the gap morphology in the CI Tau disk. The scenario that an unseen planet created the observed gap structure cannot be ruled out, although the coexistence of an eccentric hot Jupiter and a distant planet around the young CI Tau would be challenging for gravitational scattering scenarios. The mass of the planet was estimated to be between ∼0.25 MJupiter and ∼0.8 MJupiter from the gap width and depth ( ) in the modeled surface brightness image, which is lower than the current detection limits of high-contrast direct imaging. The young classical T-Tauri CI Tau may be a unique system for exploring the existence of a potential distant planet as well as the origin of an eccentric hot Jupiter.