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首页> 外文学位 >The variability of three O-type stars: zeta Ophiuchi; zeta Puppis; and HD 93521.
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The variability of three O-type stars: zeta Ophiuchi; zeta Puppis; and HD 93521.

机译：三颗O型恒星的变异性：zeta蛇夫座； Zeta Puppis;和高清95321。

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摘要

Analysis of time-resolved optical spectroscopy of the rapidly rotating O-stars: zeta Ophiuchi (O9.5 V); zeta Puppis (O4 I(n)f); and HD 93521 (O9.5 V), is presented. Extensive datasets were acquired for the first two stars, including coordinated, multi-observatory observations; these stars represent the principal subjects for investigation. For HD 93521, the data are more fragmentary; however, the echelle nature of the spectra and the similar spectral classification to zeta Oph, justify their inclusion. For all three stars, the optical observations show line profile variations (1pv) in the form of 'bumps' and 'dips' migrating from blue to red on typical timescales of several hours. Strong changes in line shape and equivalent width are also observed for zeta Pup. The strength of these variations is dependent upon line species and line strength in all cases. For the two principal stars, the morphology of the lpv is investigated by using a Fourier time-series technique which incorporates the CLEAN deconvolution algorithm. The lpv of the HD 93521 is investigated by comparison with synthetic data generated by a non-radial pulsation (NRP) stellar model. The origin of the lpv in O-stars is controversial; a major aim of this work is to discriminate between photospheric non-radial pulsation, rotational modulation, and variability at the base of the stellar wind, as the cause of the optical variability. In addition to the optical spectroscopy, narrow-band photometry was available for the primary stars, and, for all three stars, time-resolved IUE ultraviolet spectroscopy (some simultaneous with the optical data). The simultaneous UV data are of particular importance as they allow an investigation of a possible 'photospheric connection' between the lpv and the development of enhancements in optical depth within the stellar wind seen as discrete and narrow absorption components in the UV resonance lines. As a collateral study, the analysis techniques which have been applied to the optical data have been tested on a series of synthetic profiles generated by NRP stellar models. The results from the synthetic data allow a comparison with those obtained on observational data, both given here and in previous studies.
机译：快速旋转的O型星的时间分辨光谱分析：Zeta Ophiuchi（O9.5 V）; Zeta Puppis（O4 I（n）f）;以及HD 93521（O9.5 V）。前两个恒星获得了广泛的数据集，包括协调的多天文台观测；这些星星代表了调查的主要对象。对于HD 93521，数据更加零碎。但是，光谱的echelle性质和类似于zeta Oph的光谱分类证明了它们的合理性。对于所有三颗恒星，光学观测均显示出线轮廓变化（1pv），形式为“凸点”和“倾角”，在几个小时的典型时间尺度上从蓝色迁移到红色。对于zeta Pup，线形和等效宽度也发生了很大变化。在所有情况下，这些变化的强度取决于线的种类和线的强度。对于两个主恒星，通过使用结合了CLEAN解卷积算法的傅立叶时间序列技术研究了lpv的形态。通过与非径向脉动（NRP）恒星模型生成的合成数据进行比较，研究了HD 93521的lpv。 O型星中lpv的起源是有争议的；这项工作的主要目的是区分光球非径向脉动，旋转调制和恒星风基部的可变性，这是光学可变性的原因。除光谱学外，初生恒星还可以使用窄带光度法，对于所有三颗恒星，还可以使用时间分辨的IUE紫外光谱法（有些与光学数据同时进行）。同时的紫外线数据特别重要，因为它们允许研究lpv之间可能的“光球连接”，以及星状风中光学深度的增强（被视为紫外线共振线中的离散和狭窄的吸收分量），从而得到发展。作为附带研究，已经对由NRP恒星模型生成的一系列合成剖面测试了应用于光学数据的分析技术。综合数据的结果可以与此处和先前研究中给出的观测数据进行比较。

著录项

  • 作者

    Reid, Andrew Harold Noble.;

  • 作者单位

    University of London, University College London (United Kingdom).;

  • 授予单位 University of London, University College London (United Kingdom).;
  • 学科 Astronomy.
  • 学位 Ph.D.
  • 年度 1994
  • 页码 299 p.
  • 总页数 299
  • 原文格式 PDF
  • 正文语种 eng
  • 中图分类
  • 关键词

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