A HERSCHEL VIEW OF PROTOPLANETARY DISKS IN THE σ ORI CLUSTER
A HERSCHEL VIEW OF PROTOPLANETARY DISKS IN THE σ ORI CLUSTER
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DOI：
10.3847/0004-637x/829/1/38
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发表时间：
2016-07
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通讯作者：
K. Maucó;J. Hern'andez;N. Calvet;J. Ballesteros-Paredes;C. Briceño;M. McClure;P. D’Alessio;Kassandra R. Anderson;B. Ali
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作者：
K. Maucó;J. Hern'andez;N. Calvet;J. Ballesteros-Paredes;C. Briceño;M. McClure;P. D’Alessio;Kassandra R. Anderson;B. Ali
利用光电探测器阵列相机和光谱仪对年轻的猎户座σ星团中的32颗金牛座T星进行了新的赫歇尔观测。我们的大多数天体是K和M星，在24 μm处有很大的过剩。我们使用D'Alessio等人的辐射吸积盘模型，将它们的光谱能量分布与我们的观测数据进行比较。我们得出以下六个结论。(i)观察到的磁盘是一致的辐照吸积盘系统。(ii)我们的大多数物体（60%）可以用来自磁盘上层的显着尘埃消耗来解释。(iii)类似地，我们的61%的对象可以用大的磁盘大小（Rd ≥ 100 Au）建模。(iv)我们的盘的质量范围在0.03到39 MJup之间，其中35%的物体的盘质量小于1 MJup。虽然这些是下限，但存在于例如，金牛座，不见了。(v)通过假设星系团中心最亮的恒星周围的物体均匀分布，我们发现80%的圆盘暴露在外部FUV辐射下，这种辐射足以使较近圆盘的外边缘光蒸发。(vi)在距离σ Ori 0.6 pc的范围内，我们在我们的一个大圆盘（SO 662）的光谱中发现了[N ii]的禁发射线，但在我们的任何一个小圆盘中都没有发射。这表明这个物体可能是光蒸发盘的一个例子。
We present new Herschel observations using the Photodetector Array Camera and Spectrometer of 32 T Tauri stars in the young (∼3 Myr) σ Ori cluster. Most of our objects are K and M stars with large excesses at 24 μm. We used irradiated accretion disk models of D’Alessio et al. to compare their spectral energy distributions with our observational data. We arrive at the following six conclusions. (i) The observed disks are consistent with irradiated accretion disk systems. (ii) Most of our objects (60%) can be explained by significant dust depletion from the upper disk layers. (iii) Similarly, 61% of our objects can be modeled with large disk sizes (Rd ≥ 100 au). (iv) The masses of our disks range between 0.03 and 39 MJup, where 35% of our objects have disk masses less than 1 MJup. Although these are lower limits, high-mass (>0.05 ) disks, which are present in, e.g., Taurus, are missing. (v) By assuming a uniform distribution of objects around the brightest stars at the center of the cluster, we found that 80% of our disks are exposed to external FUV radiation of , which can be strong enough to photoevaporate the outer edges of the closer disks. (vi) Within 0.6 pc from σ Ori we found forbidden emission lines of [N ii] in the spectrum of one of our large disks (SO662), but no emission in any of our small ones. This suggests that this object may be an example of a photoevaporating disk.