Massive star feedback in clusters: variation of the FUV interstellar radiation field in time and space
Massive star feedback in clusters: variation of the FUV interstellar radiation field in time and space
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DOI：
10.1093/mnras/stz1673
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发表时间：
2019-06
影响因子：
4.8
通讯作者：
A. Ali;T. Harries
中科院分区：
文献类型：
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作者：
A. Ali;T. Harries
我们使用三维辐射-流体动力学（RHD）模型研究了$10^4$ M $_\odot$湍流云中34 M $_\odot$恒星的辐射反馈。我们利用蒙特卡罗辐射传输技术精确地计算了多原子种和硅酸盐粉尘颗粒的光电离平衡和辐射压力。我们包括漫射辐射场、尘埃吸收/再发射和散射。云被有效地分散，75％的质量在4.3迈尔（1.1 $t_{ff}$）内离开（32.3 pc） $^3$网格。这与我们之前发表的$10^3$ M $_\odot$云中1.6 Myr （0.74 $t_{ff}$）以内的所有质量进行了比较。最多有20％的质量被电离，而在低质量模型中是40％，尽管两者的电离体积分数都是80％，这意味着高质量云对反馈的适应性更强。总jeans -不稳定质量线性增加到1500 M $_\odot$，然后在2 Myr之后趋于稳定，对应于15％的核心形成效率。我们还测量了远紫外（FUV）辐射场的时间变化$G_0$，影响到其他星团成员，首次考虑到这种变化如何在动态星团环境中与不透明源和恒星运动的干预。许多物体在前0.5 Myr被屏蔽，而大质量恒星被嵌入，在此之后$G_0$增加了几个数量级。随后的气体运动导致类似的瞬间下降，持续$\sim$ 1 Myr，然后恢复。这种高度可变的紫外场将影响大质量恒星附近原行星盘的光蒸发。
We investigate radiative feedback from a 34 M$_\odot$ star in a $10^4$ M$_\odot$ turbulent cloud using three-dimensional radiation-hydrodynamics (RHD) models. We use Monte Carlo radiative transfer to accurately compute photoionization equilibrium and radiation pressure, with multiple atomic species and silicate dust grains. We include the diffuse radiation field, dust absorption/re-emission, and scattering. The cloud is efficiently dispersed, with 75 per cent of the mass leaving the (32.3 pc)$^3$ grid within 4.3 Myr (1.1 $t_{ff}$). This compares to all mass exiting within 1.6 Myr (0.74 $t_{ff}$) in our previously published $10^3$ M$_\odot$ cloud. At most 20 per cent of the mass is ionized, compared to 40 per cent in the lower mass model, despite the ionized volume fraction being 80 per cent in both, implying the higher mass cloud is more resilient to feedback. The total Jeans-unstable mass increases linearly up to 1500 M$_\odot$ before plateauing after 2 Myr, corresponding to a core formation efficiency of 15 per cent. We also measure the time-variation of the far-ultraviolet (FUV) radiation field, $G_0$, impinging on other cluster members, taking into account for the first time how this changes in a dynamic cluster environment with intervening opacity sources and stellar motions. Many objects remain shielded in the first 0.5 Myr whilst the massive star is embedded, after which $G_0$ increases by orders of magnitude. Gas motions later on cause comparable drops which happen instantaneously and last for $\sim$ 1 Myr before being restored. This highly variable UV field will influence the photoevaporation of protoplanetary discs near massive stars.