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arXiv 1701.01124astro-ph.SR
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数值模拟和红外光谱干涉技术揭示了gamma2 Velorum中的风碰撞区

Numerical simulations and infrared spectro-interferometry reveal the wind collision region in gamma2 Velorum

A. Lamberts, F. Millour, A. Liermann, L. Dessart, T. Driebe, G. Duvert, W. Finsterle, V. Girault, F. Massi, R. G. Petrov, W. Schmutz, G. Weigelt, O. Chesneau

摘要:

几十年来,人们一直通过射电、光学线路和强X射线辐射来研究大质量双星系统中的碰撞恒星风。最近,近红外光谱干涉仪观测已在少数系统中可用,但隔离个别恒星和风碰撞区域的贡献仍然是一个挑战。本文研究了碰撞风双星伽玛2 Velorum,旨在从红外干涉数据中识别风碰撞区,这为确定风的性质提供了独特的空间信息。我们的分析是基于多历元VLTI/AMBER数据,使我们能够分离两颗恒星的光谱分量。首先,我们确定的天体测量解决方案的二进制和确认以前的距离测量。然后,我们分析了个别恒星的光谱,表明O星的光谱是特殊的。然后,我们对系统进行三维流体动力学模拟,从中提取模型图像、可见性曲线和闭合阶段,可以直接与观测数据进行比较。流体动力学模拟揭示了风碰撞区域的三维螺旋结构,这导致相位相关的发射图。当风碰撞区域占近红外总通量的3%至10%时,我们的模型能见度曲线和闭合阶段提供了很好的匹配。流体动力学模拟、辐射转移模型和观测之间的对话使我们能够充分利用观测结果。类似的努力对于使用新一代VLTI仪器(如重力和MATISSE)研究星周环境至关重要。

英文摘要:

Colliding stellar winds in massive binary systems have been studied through their radio, optical lines and strong X-ray emission for decades. More recently, near-infrared spectrointerferometric observations have become available in a few systems, but isolating the contribution from the individual stars and the wind collision region still remains a challenge. In this paper, we study the colliding wind binary gamma2 Velorum and aim at identifying the wind collision zone from infrared interferometric data, which provide unique spatial information to determine the wind properties. Our analysis is based on multi-epoch VLTI/AMBER data that allows us to separate the spectral components of both stars. First, we determine the astrometric solution of the binary and confirm previous distance measurements. We then analyse the spectra of the individual stars, showing that the O star spectrum is peculiar within its class. Then, we perform three-dimensional hydrodynamic simulations of the system from which we extract model images, visibility curves and closure phases which can be directly compared with the observed data. The hydrodynamic simulations reveal the 3D spiral structure of the wind collision region, which results in phase-dependent emission maps. Our model visibility curves and closure phases provide a good match when the wind collision region accounts for 3 to 10 per cent of the total flux in the near infrared. The dialogue between hydrodynamic simulations, radiative transfer models and observations allows us to fully exploit the observations. Similar efforts will be crucial to study circumstellar environments with the new generation of VLTI instruments like GRAVITY and MATISSE.

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。

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