Pinwheels in the sky, with dust : 3D modelling of the Wolf-Rayet 98a environment
Pinwheels in the sky, with dust : 3D modelling of the Wolf-Rayet 98a environment
复制标题
天空中的风车，尘土飞扬：Wolf-Rayet 98a 环境的 3D 建模
DOI：
10.1093/mnras/stw1289
复制
发表时间：
2016
影响因子：
4.8
通讯作者：
Z. Meliani
中科院分区：
文献类型：
--
作者：
T. Hendrix;R. Keppens;A. J. Marle;P. Camps;M. Baes;Z. Meliani
Wolf-Rayet 98 a（WR 98 a）系统是干涉测量的主要目标，因为它被识别为“旋转风车星云”，红外图像显示螺旋尘埃带以1.4年的周期旋转。WR 98 a拥有一颗WC 9 +OB星星，考虑到沃尔夫-拉叶星的极端光度，尘埃的存在令人困惑。我们提出了WR 98 a的三维流体动力学模型，其中灰尘的产生和重新分布是自洽的。我们的网格自适应模拟解决风碰撞区域的细节在尺度低于百分之一的轨道分离（类似于4 Au），而模拟高达1300 Au。我们涵盖了几个轨道周期的条件下，气体成分单独的行为绝热，或受到有效的辐射冷却。在绝热的情况下，恒星风之间的混合在一个定义明确的螺旋模式中是有效的，在那里满足了尘埃产生的最佳条件。当辐射冷却被纳入，相互作用得到占主导地位的热不稳定性沿着风碰撞区，尘埃集中在团块和细丝在体积填充的方式，所以WR 98 a必须服从接近绝热演变证明旋转风车结构。我们模仿凯克，阿尔马或未来的E-ELT观测和面对测光长期监测。我们预测的螺旋形的前缘和后缘之间的尘埃分布的不对称性，表明阿尔马和E-ELT将能够检测到的螺旋形的精细结构指示开尔文-亥姆霍兹发展，并确认测光的变化，由于方向。历史凯克图像被复制，但它们的分辨率不足以检测到我们预测的细节。
The Wolf-Rayet 98a (WR 98a) system is a prime target for interferometric surveys, since its identification as a 'rotating pinwheel nebulae', where infrared images display a spiral dust lane revolving with a 1.4 yr periodicity. WR 98a hosts a WC9+OB star, and the presence of dust is puzzling given the extreme luminosities of Wolf-Rayet stars. We present 3D hydrodynamic models for WR 98a, where dust creation and redistribution are self-consistently incorporated. Our grid-adaptive simulations resolve details in the wind collision region at scales below one percent of the orbital separation (similar to 4 au), while simulating up to 1300 au. We cover several orbital periods under conditions where the gas component alone behaves adiabatic, or is subject to effective radiative cooling. In the adiabatic case, mixing between stellar winds is effective in a well-defined spiral pattern, where optimal conditions for dust creation are met. When radiative cooling is incorporated, the interaction gets dominated by thermal instabilities along the wind collision region, and dust concentrates in clumps and filaments in a volume-filling fashion, so WR 98a must obey close to adiabatic evolutions to demonstrate the rotating pinwheel structure. We mimic Keck, ALMA or future E-ELT observations and confront photometric long-term monitoring. We predict an asymmetry in the dust distribution between leading and trailing edge of the spiral, show that ALMA and E-ELT would be able to detect fine-structure in the spiral indicative of Kelvin-Helmholtz development, and confirm the variation in photometry due to the orientation. Historic Keck images are reproduced, but their resolution is insufficient to detect the details we predict.
银河系 WC 恒星光谱分析的恒星参数表明了新的演化序列
DOI：
10.1051/0004-6361/201117830
发表时间：
2012
期刊：
arXiv: Solar and Stellar Astrophysics
影响因子：
--
作者：
A. Sander;W.-R. Hamann;H. Todt
通讯作者：
H. Todt