Signature of wide-spread clumping in B supergiant winds
Signature of wide-spread clumping in B supergiant winds
复制标题
B超巨风中广泛聚集的特征
DOI：
--
复制
发表时间：
2010
期刊：
影响因子：
--
通讯作者：
D. Massa
中科院分区：
文献类型：
--
作者：
R. Prinja;D. Massa
目标。我们寻求建立OB星星风聚集效应的额外观测特征。聚集在战略风形成的谱线上的行动进行测试，以引导发展模型的聚集风，从而提高大质量恒星的质量损失测定的可靠性。方法.用经验谱线合成模型分析了B 0 ~ B5超巨星的Siiv λλ1400共振线偶。重点是从Siiv双合线的红色和蓝色分量的径向光学深度（τrad（w））的测量值中解码关于风聚集的信息。我们特别利用的事实，即两个偶极子组件是解耦的，并形成独立的风终端速度相对较低的目标。结果线合成分析表明，蓝色与红色Siiv分量的τrad（w）的平均比很少接近规范值2（根据原子常数预期），而是分布在1和2之间的值范围内。这些结果被解释的光球，部分被光学厚结构的外流气体。结论.在这项研究中建立的光谱特征证明了广泛存在的风聚集在B超巨星。非饱和偶极子剖面中的附加信息提供了一种量化风的孔隙度的方法。
Aims. We seek to establish additional observational signatures of the effects of clumping in OB star winds. The action of clumping on strategic wind-formed spectral lines is tested to steer the development of models for clumped winds and thus improve the reliability of mass-loss determinations for massive stars. Methods. The Siiv λλ1400 resonance line doublets of B0 to B5 supergiants are analysed using empirical line-synthesis models. The focus is on decoding information on wind clumping from measurements of ratios of the radial optical depths (τrad(w)) of the red and blue components of the Siiv doublet. We exploit in particular the fact that the two doublet components are decoupled and formed independently for targets with relatively low wind terminal velocities. Results. Line-synthesis analyses reveal that the mean ratio of τrad(w) of the blue to red Siiv components are rarely close to the canonical value of ∼2 (expected from atomic constants), and spread instead over a range of values between ∼1 and 2. These results are interpreted in terms of a photosphere that is partially obscured by optically thick structures in the outflowing gas. Conclusions. The spectroscopic signatures established in this study demonstrate the wide-spread existence of wind clumping in B supergiants. The additional information in unsaturated doublet profiles provides a means to quantify the porosity of the winds.