arXivDaily arXiv每日学术速递 周一至周五更新
arXiv 0905.3542astro-ph.SR
收藏

共生双星风吸积的数值模拟

Numerical Simulations of Wind Accretion in Symbiotic Binaries

M. de Val-Borro, M. Karovska, D. Sasselov

摘要:

研究了伴星引力聚焦对晚型星风的动力学效应。特别是,我们调查的质量转移和形成吸积盘周围的辅助分离系统组成的AGB质量损失的恒星和吸积的同伴。质量外流的存在作为一个函数的质量损失率,风温和二进制轨道参数进行了研究。利用二维流体动力学模型研究了风吸积共生二元系统中质量传递的稳定性。在我们的模拟中,我们使用绝热状态方程和等温近似的修改版本,其中温度取决于质量损失恒星及其伴星的距离。我们探讨的吸积流之间的组件和形成的吸积盘的轨道分离和风参数的范围。我们的结果表明,对于某些轨道配置,恒星和各种大小的吸积盘之间形成了流流。对于一个典型的缓慢和大规模的风从AGB星的流动模式是类似的RLOF与吸积率的10%的质量损失从主要的。当风在几个恒星半径处加速时,就会形成密度呈指数递减、质量达到$10^{-4}$太阳质量量级的稳定盘。潮汐流和吸积盘的形成被认为是弱依赖于从AGB星的质量损失。我们的模拟引力集中风吸积在共生双星显示流流动和增强吸积率到紧凑的组件的形成。

英文摘要:

We study the dynamical effects of gravitational focusing by a binary companion on winds from late-type stars. In particular, we investigate the mass transfer and formation of accretion disks around the secondary in detached systems consisting of an AGB mass-losing star and an accreting companion. The presence of mass outflows is studied as a function of mass loss rate, wind temperature and binary orbital parameters. A 2-dimensional hydrodynamical model is used to study the stability of mass transfer in wind accreting symbiotic binary systems. In our simulations we use an adiabatic equation of state and a modified version of the isothermal approximation, where the temperature depends on the distance from the mass losing star and its companion. We explore the accretion flow between the components and formation of accretion disks for a range of orbital separations and wind parameters. Our results show the formation of stream flow between the stars and accretion disks of various sizes for certain orbital configurations. For a typical slow and massive wind from an AGB star the flow pattern is similar to a RLOF with accretion rates of 10% of the mass loss from the primary. Stable disks with exponentially decreasing density profiles and masses of the order $10^{-4}$ solar masses are formed when wind acceleration occurs at several stellar radii. The formation of tidal streams and accretion disks is found to be weakly dependent on the mass loss from the AGB star. Our simulations of gravitationally focused wind accretion in symbiotic binaries show the formation of stream flows and enhanced accretion rates onto the compact component.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

↑