论文标题
星际灭绝曲线形状的分析。 viii。光学灭绝结构
An Analysis of the Shapes of Interstellar Extinction Curves. VIII. The Optical Extinction Structure
论文作者
论文摘要
对于现有IUE紫外光谱的早期类型恒星样品，获得了新的HST/STIS光谱。这些数据用于构建光学灭绝曲线的一般特性在其他地方讨论。在本文中，我们确定曲线中的消光特征比漫射的星际频段（DIB）宽，但比众所周知的宽带变异性窄。这种中级规模的结构或ISS包含不同的特征，其峰值可以贡献总灭绝的百分比至20％。大多数ISS变异可以由三个主要组件捕获。我们用三个drude配置文件对ISS进行建模，并表明它们的优势和宽度从一个视线到另一个视线不等，但它们的中心位置稳定，接近4370、4870和6300A。光曲线中非常宽的结构VBS似乎是4870和6300A吸收峰之间的最小值。我们发现拟合参数之间的关系，并根据简单的谷物模型提供了对它们的物理解释。最后，我们注意到4370和4870a功能的优势与2175a UV颠簸的强度相关，但是6300A的功能却没有，并且ISS功能都与R（V）无关。但是，我们验证连续光学灭绝的宽带曲率与R（V）密切相关。
New HST/STIS optical spectra were obtained for a sample of early type stars with existing IUE UV spectra. These data were used to construct optical extinction curves whose general properties are discussed elsewhere. In this paper, we identify extinction features in the curves that are wider than diffuse interstellar bands (DIBs) but narrower than the well known broad band variability. This intermediate scale structure, or ISS, contains distinct features whose peaks can contribute a few percent to 20% of the total extinction. Most of the ISS variation can be captured by three principal components. We model the ISS with three Drude profiles and show that their strengths and widths vary from one sight line to another, but their central positions are stable, near 4370, 4870 and 6300A. The Very Broad Structure, VBS, in optical curves appears to be a minimum between the 4870 and 6300A absorption peaks. We find relations among the fit parameters and provide a physical interpretation of them in terms of a simplistic grain model. Finally, we note that the strengths of the 4370 and 4870A features are correlated to the strength of the 2175A UV bump, but that the 6300A feature is not, and that none of the ISS features are related to R(V). However, we verify that the broad band curvature of the continuous optical extinction is strongly related to R(V).
