Modeling the gas-phase chemistry of the transitional disk around HD 141569A
Modeling the gas-phase chemistry of the transitional disk around HD 141569A
复制标题
对 HD 141569A 周围过渡盘的气相化学进行建模
DOI：
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发表时间：
2006
期刊：
影响因子：
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通讯作者：
E. F. Dishoeck
中科院分区：
文献类型：
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作者：
B. Jonkheid;I. Kamp;J. Augereau;E. F. Dishoeck
目标。5myr年老的B9.5 V恒星HD 141569A周围的过渡盘中气体的化学成分、分布和质量受到限制。方法。利用光子主导区（PDR）的准二维化学代码计算了盘内的化学温度和气体温度。计算了几种气体分布、多环芳烃丰度和总气体质量值。用二维辐射传输码计算得到CO $J=2{-}1$和$J=3{-}2$发射线，并与观测值进行比较。结果。CO丰度对圆盘的总质量非常敏感，因为圆盘处于自屏蔽状态。观测到的CO发射谱线最符合从距中心恒星80 AU处开始的$80~ m_o + $的幂律气体分布，这表明内孔中存在一些气体。对原子精细结构线的强度进行了预测。[$ion{C}{i}$]是圆盘大部分碳的主要形式，是气体质量的一种很好的替代示踪剂。
Aims. The chemistry, distribution and mass of the gas in the transitional disk around the 5 Myr old B9.5 V star HD 141569A are constrained. Methods. A quasi 2-dimensional (2D) chemistry code for photon dominated regions (PDR) is used to calculate the chemistry and gas temperatures in the disk. The calculations are performed for several gas distributions, PAH abundances and values of the total gas mass. The resulting CO $J=2{-}1$ and $J=3{-}2$ emission lines are computed with a 2D radiative transfer code and are compared to observations. Results. The CO abundance is very sensitive to the total disk mass because the disk is in a regime where self-shielding just sets in. The observed CO emission lines are best fit by a power-law gas distribution of $80~M_oplus$ starting at 80 AU from the central star, indicating that there is some gas in the inner hole. Predictions are made for intensities of atomic fine-structure lines. [$ion{C}{i}$], which is the dominant form of carbon in large parts of the disk, is found to be a good alternative tracer of the gas mass.