Rapid Variability in the Spectral Lines of Be Stars

Be星光谱线的快速变化

• 批准号: 8917740
• 负责人: Douglas Gies
• 金额: $ 2.96万
• 依托单位: Georgia State University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 1989
• 资助国家: 美国
• 起止时间: 1989-09-15 至 1991-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=8917740&HistoricalAwards=false
• 关键词: Rapid; Variability; Spectral; Lines; Stars

Stars have wide ranges of masses, ages, rotation rates, and other physical properties. For example, Be stars are relatively young, rapidly rotating stars of type B, with surface temperatures above 10,000 K and characteristic emission features (hence, the "e" in Be) in their hydrogen Balmer lines. During the last few years, photometric and spectroscopic observations have revealed variations in the colors and in the absorption lines of Be stars that move from the blue to the red, on time scales of 0.2 to 2 days, and that so far have defied unique physical explanation. Vogt and Penrod have interpreted these variations as being due to nonradial pulsations (NRPs) in the stars' photospheres. The PI will test the NRP model with a time series analysis of the stars' absorption line variations. Furthermore, he will compare variations in the stars' photospheres, circumstellar disks, and high velocity winds to determine whether the proposed NRPs are responsible for the mass loss observed from these and, possibly, other rapidly rotating stars.

恒星具有广泛的质量，年龄，旋转速率和其他物理特性。 例如，BE恒星相对年轻，迅速旋转的B型恒星，表面温度高于10,000 K，并且在其氢Balmer系列中的特征发射特征（因此，BE中的“ E”）。 在过去的几年中，光度法和光谱观察结果揭示了颜色和恒星的吸收线的变化，这些恒星的吸收线从蓝色转变为红色，按时间尺度为0.2至2天，到目前为止，迄今为止违反了独特的物理解释。 Vogt和Penrod将这些变化解释为归因于恒星光传球中的非自由搏动（NRP）。 PI将通过恒星吸收线变化的时间序列分析来测试NRP模型。 此外，他将比较恒星的光角，偶然磁盘和高速风的变化，以确定所提出的NRP是否负责从这些质量损失以及其他快速旋转的恒星观察到的质量损失。