iVINE – Ionization in the parallel tree/sph code VINE: first results on the observed age‐spread around O‐stars
iVINE – Ionization in the parallel tree/sph code VINE: first results on the observed age‐spread around O‐stars
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DOI：
10.1111/j.1365-2966.2008.14185.x
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发表时间：
2008-09
影响因子：
4.8
通讯作者：
M. Gritschneder;T. Naab;Andreas Burkert;S. Walch;F. Heitsch;M. Wetzstein
中科院分区：
文献类型：
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作者：
M. Gritschneder;T. Naab;Andreas Burkert;S. Walch;F. Heitsch;M. Wetzstein
我们提出了一个三维的，完全并行的，有效的实现电离紫外线（UV）辐射的平滑粒子流体动力学（SPH），包括自重力。我们的方法是基于SPH/TREE代码VINE。因此我们称之为iVINE（电离+ VINE）。这种方法可以对电离辐射的影响进行详细的高分辨率研究，例如，年轻的大质量恒星对其湍流母体分子云的影响。在本文中，我们描述了平面平行几何辐射传递的概念和数值实现，并讨论了几个测试案例，证明了新方法的效率和准确性。作为第一个应用，我们研究了在强紫外源的不同距离上边缘稳定分子云的辐射驱动内爆，并表明它们被驱动成引力坍缩。得到的内核非常紧凑和密集，就像在集群环境中观察到的那样。我们的模拟表明，触发坍缩的时间取决于核心与紫外线源的距离。离源较近的云比离源较远的云早坍缩10 ~ 5年。这种效应可以解释观测到的OB星群的年龄分布，在OB星群中，离源更近的恒星被发现更年轻。我们讨论了由于电离辐射早期剥离原恒星包层而在激波前速度的观测推导中可能存在的不确定性。
We present a three-dimensional, fully parallelized, efficient implementation of ionizing ultraviolet (UV) radiation for smoothed particle hydrodynamics (SPH) including self-gravity. Our method is based on the SPH/TREE code VINE. We therefore call it iVINE (for Ionization + VINE). This approach allows detailed high-resolution studies of the effects of ionizing radiation from, for example, young massive stars on their turbulent parental molecular clouds. In this paper, we describe the concept and the numerical implementation of the radiative transfer for a plane-parallel geometry and we discuss several test cases demonstrating the efficiency and accuracy of the new method. As a first application, we study the radiatively driven implosion of marginally stable molecular clouds at various distances of a strong UV source and show that they are driven into gravitational collapse. The resulting cores are very compact and dense exactly as it is observed in clustered environments. Our simulations indicate that the time of triggered collapse depends on the distance of the core from the UV source. Clouds closer to the source collapse several 10 5 yr earlier than more distant clouds. This effect can explain the observed age spread in OB associations where stars closer to the source are found to be younger. We discuss possible uncertainties in the observational derivation of shock front velocities due to early stripping of protostellar envelopes by ionizing radiation.