Seismic studies of the global Sun with BiSON

使用 BiSON 对全球太阳进行地震研究

• 批准号: PP/E000940/1
• 负责人: Yvonne Elsworth
• 金额: $ 297.7万
• 依托单位: University of Birmingham
• 依托单位国家: 英国
• 项目类别: Research Grant
• 财政年份: 2007
• 资助国家: 英国
• 起止时间: 2007 至 无数据
• 项目状态: 已结题
• 来源: https://gtr.ukri.org/projects?ref=PP%2FE000940%2F1
• 关键词: Seismic; studies; global; Sun; BiSON

The Sun is vital to life on Earth. Our research aims are to 'look' deep inside the Sun to help us understand how it works. Although you can't see it without special equipment, the Sun is shaking. Bubbling motion just under the visible surface of the Sun is constantly feeding in energy, and the Sun responds by vibrating just like a (very) large musical instrument. The 'notes' of the Sun's music are very interesting to astronomers. They are produced by sound waves which have travelled deep inside and their frequencies (the 'pitches' of the notes) depend on the conditions they meet on the way. For example, the frequencies depend on the density and temperature of the material inside the Sun and studying them allows astronomers to essentially get an 'ultrasound scan' of our nearest star. Actually turning these ideas into scientific reality is very difficult. The shaking of the Sun's surface is very small - it moves to and fro at a couple of metres per second (a slow walking pace), and takes about 5 minutes to go through a cycle. Just detecting this small movement takes specially designed instruments (called spectrometers, because they analyse the spectrum of sunlight). Some interesting effects on the Sun can last for several years. For example, there is a cycle of magnetic activity (which we don't fully understand yet) which makes the Sun have periods of 'spottiness' every 11 years or so. For this and other reasons, you would really like to observe the Sun's vibrations all the time over many years. One way of doing this is to have a number of robotic spectrometers in different sunny locations around the world, so that when the Sun sets on one instrument it has already risen on another. The Birmingham Solar Oscillations Network (BiSON) is just such a 'network' of spectrometers - there are 6 instruments in good sites for solar viewing in the Americas, Australia, Tenerife and South Africa. We designed and built these dedicated instruments, and we maintain and update them with local support and by visits by team members. The data are returned to our base in Birmingham via the Internet, and the remote link also lets us monitor the performance of the instruments and upgrade some of the software. Results from BiSON have been very important in helping astronomers to understand the Sun. The spectrum of the Sun's deepest vibrations was first detected by BiSON, and we continue to provide and analyse data which can help us to improve our understanding of everything from what makes the vibrations in the first place, all the way to information about the nuclear reactor at the Sun's core. Astronomers are beginning to measure the interiors of other stars, and our work on the Sun provides an important reference point for this new work. The effects we study are very subtle, and we spend much of our effort in analysing the data. To confirm that our results are 'real', we compare our results with those obtained by the small number of other astronomers who have similar equipment, and we also test our analysis programs on sophisticated artificial data sets which mimic as closely as we can the real thing. The beauty of simulated data is that you know exactly what went into them, so if you run your analysis programs you know what the output should look like. We have used simulated data for some years now, but as we have learned more about our instruments, we now know that there are several subtle effects which occur in real data that we've not yet built into our simulation programs. So our new proposal is to continue to maintain the BiSON network and collect high quality data. We will use these and other data to provide new information on the deep interior of the Sun (and inform the study of other stars), improve our understanding of the solar cycle and of the outer convective layers of the Sun where the vibrations are generated.

太阳对地球上的生命至关重要。我们的研究目的是“看”太阳内部深处，以帮助我们了解它是如何工作的。虽然没有特殊设备你看不到它，但太阳正在摇晃。太阳可见表面下的气泡运动不断地提供能量，太阳的反应是像一个（非常）大的乐器一样振动。太阳音乐的“音符”对天文学家来说非常有趣。它们是由深入内部的声波产生的，它们的频率（音符的“音高”）取决于它们在途中遇到的条件。例如，频率取决于太阳内部物质的密度和温度，研究它们可以让天文学家基本上获得离我们最近的星星的“超声扫描”。实际上把这些想法变成科学现实是非常困难的。太阳表面的震动非常小-它以每秒几米的速度来回移动（缓慢的步行速度），大约需要5分钟才能完成一个周期。光是检测这种微小的运动就需要专门设计的仪器（称为光谱仪，因为它们分析太阳光的光谱）。太阳上一些有趣的影响可以持续数年。例如，有一个磁场活动的周期（我们还没有完全理解），这使得太阳每11年左右就有一个“斑点”周期。因为这个和其他的原因，你们真的很想在许多年里一直观察太阳的振动。其中一种方法是在世界各地不同的阳光充足的地方放置许多机器人光谱仪，这样当太阳在一台仪器上落下时，它已经在另一台仪器上升起了。伯明翰太阳振荡网络（野牛）就是这样一个光谱仪的“网络”-在美洲，澳大利亚，特内里费岛和南非的太阳观测地点有6台仪器。我们设计和建造了这些专用仪器，并通过当地支持和团队成员的访问对其进行维护和更新。数据通过互联网返回到我们在伯明翰的基地，远程链接还允许我们监控仪器的性能并升级一些软件。野牛的结果在帮助天文学家了解太阳方面非常重要。太阳最深处振动的光谱首先由野牛探测到，我们将继续提供和分析数据，这些数据可以帮助我们提高对一切的理解，从最初产生振动的原因，一直到关于太阳核心核反应堆的信息。天文学家开始测量其他恒星的内部，我们对太阳的研究为这项新工作提供了重要的参考点。我们研究的影响是非常微妙的，我们花了很多精力分析数据。为了确认我们的结果是“真实的”，我们将我们的结果与少数拥有类似设备的其他天文学家获得的结果进行了比较，我们还在复杂的人工数据集上测试了我们的分析程序，这些数据集尽可能地模仿了真实的事物。模拟数据的美妙之处在于，你确切地知道它们是什么，所以如果你运行你的分析程序，你就知道输出应该是什么样子。我们使用模拟数据已经有几年了，但随着我们对仪器了解的更多，我们现在知道在真实的数据中存在一些微妙的影响，我们尚未将其构建到我们的模拟程序中。因此，我们的新建议是继续维护野牛网络并收集高质量的数据。我们将利用这些数据和其他数据来提供关于太阳内部深处的新信息（并为其他恒星的研究提供信息），提高我们对太阳周期和产生振动的太阳外对流层的理解。