Seismology of the Surface Layers of Stars

恒星表面层的地震学

• 批准号: 155320-2012
• 负责人: Guenther, David
• 金额: $ 1.82万
• 依托单位: Saint Mary's University
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2015
• 资助国家: 加拿大
• 起止时间: 2015-01-01 至 2016-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=569443
• 关键词: Seismology; Surface; Layers; Stars

My research is primarily directed toward understanding how stars work by analyzing the harmonic structure of sound waves that bounce around their interiors. The sound waves are not heard but seen. As a sound wave travels through the interior of a star it causes the material of the star to oscillate up and down into warmer and cooler regions of the star. The changes in temperature of the material can be seen on the surface of a star as minute variations in the star's brightness. From the brightness fluctuations, we can deduce the frequency and amplitudes of the sound waves, which, in turn, can be used to build a picture of what is going on inside the star. In order to clearly see the fluctuations we need to observe the same star continuously for weeks to months, without interruption from weather and daylight. In addition, we need to avoid the twinkling effects of the earth's atmosphere. Therefore, we must observe from a "space telescope" specifically designed to observe tiny variations in light. Canadian scientists were the first to build and launch (June 30, 2003) such a satellite, called MOST (Microvariability and Oscillations on STars). Since then two additional satellites, CoRoT (French Space Agency CNES) and Kepler (NASA) have been deployed. My research colleagues, students and I are analyzing the data obtained from these satellites to build a detailed picture of the interiors stars. I am primarily interested in untangling the effects that the surface layers have on a star's oscillation spectrum. All oscillation spectra are affected by the surface layers since the sound waves must pass through this layer in their journey through the star. The surface layers introduce some of most difficult-to-model physics including convection, rotation, and magnetic fields. I will model the physics and I will develop strategies to isolate the effects that the surface layer physics have on the oscillation spectrum so that I can test my models.

我的研究主要旨在通过分析在恒星内部反弹的声波的谐波结构来了解恒星的工作原理。声波不是被听到的，而是被看到的。当声波穿过恒星内部时，它会导致恒星的物质上下振荡，进入恒星较温暖和较冷的区域。在恒星表面，材料温度的变化可以被视为恒星亮度的微小变化。根据亮度波动，我们可以推断出声波的频率和振幅，进而可以用来构建恒星内部正在发生的情况的图像。 为了清楚地看到波动，我们需要连续观察同一颗恒星数周至数月，不受天气和日光的干扰。此外，我们还需要避免地球大气层的闪烁效应。因此，我们必须使用专门设计用于观察光的微小变化的“太空望远镜”进行观察。加拿大科学家率先建造并发射了（2003 年 6 月 30 日）这样的卫星，称为 MOST（恒星上的微变率和振荡）。此后又部署了两颗卫星：CoRoT（法国航天局 CNES）和开普勒（NASA）。我的研究同事、学生和我正在分析从这些卫星获得的数据，以绘制内部恒星的详细图片。 我主要感兴趣的是弄清楚表面层对恒星振荡频谱的影响。所有振荡频谱都受到表面层的影响，因为声波在穿过恒星的旅程中必须穿过该层。表面层引入了一些最难建模的物理场，包括对流、旋转和磁场。我将对物理进行建模，并制定策略来隔离表面层物理对振荡频谱的影响，以便我可以测试我的模型。