Is it bigger than a breadbox? Probing stellar secrets by modelling spectra of magnetic and other stars

比面包盒大吗？

• 批准号: RGPIN-2016-04440
• 负责人: Landstreet, John
• 金额: $ 2.4万
• 依托单位: University of Western Ontario
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2018
• 资助国家: 加拿大
• 起止时间: 2018-01-01 至 2019-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=656558
• 关键词: bigger; than; breadbox; Probing; stellar

The most obvious astronomical object in the sky, our Sun, is a typical star. At night most of what we see in the sky is other stars, bodies much like our Sun except that they come in a wide variety of sizes, surface temperatures, distance, etc. For much of the past century, many astronomers have been actively trying to obtain information about individual stars (such as how much mass each has), to understand what stars are like below their glowing surfaces (How hot and how dense is the interior? Is the material gaseous?), and particularly to understand how stars form and change, and eventually collapse to huge hot cinders.***Learning about stars requires us to squeeze as much information as possible from the faint light they send to us. This light contains an astonishing amount of information. By studying the light in detail, we can often discover how large the star is, how hot, how far away, and how massive. We can also get more detailed information about the surface layer (the star's "atmosphere''), for example how dense the gas is, what the chemical composition of the gas is, and whether the gas is quiet or is bubbling and blowing like a windy day. ***My overall research programme focusses on using starlight to try to answer specific questions about specific kinds of stars. For example, some stars are observed to be permeated by strong magnetic fields. I am looking at the fields of a number of stars that are in environments which allow us to estimate their ages, and searching for evidence of how the average magnetism of these stars changes with age, from young stars to older ones. Answering this question should help us to understand how magnetic fields grow and change in stars. ***Another aspect of my programme involves looking for very weak magnetism in white dwarf stars. These are the hot stellar corpses that result when a star like the Sun runs out of fuel and collapses to become a "tiny'' body, about as large as the earth, that simply cools through the ages. Again this should help us to understand magnetic fields in stars better. ***I am also looking at the light from stars that are so young that they still have around them some of the gas that gravity pulled together to form the new star. The gas that is close to the star but has not yet fallen onto the surface is heated by the light from the new star, and glows. This glow can be analysed to find out more about that gas - how much material is there, how hot it is, and so on. ***Each of these aspects of my research digs into a very small, specific question about stars, but the results are like pieces of a huge jigsaw puzzle - putting them all together allows us to understand better the big story of how stars form and change through their lives.**

天空中最明显的天体，我们的太阳，是一颗典型的星星。在晚上，我们在天空中看到的大多数是其他恒星，这些恒星与我们的太阳非常相似，只是它们的大小、表面温度、距离等各不相同。在过去的世纪的大部分时间里，许多天文学家一直在积极地试图获得有关单个恒星的信息（比如每颗恒星有多少质量），了解恒星在发光表面下的样子（内部有多热，密度有多大？物质是气态的吗？），特别是了解恒星如何形成和变化，并最终坍缩成巨大的热煤渣。了解恒星需要我们从它们发送给我们的微弱光线中提取尽可能多的信息。这些光包含了惊人的信息量。通过详细地研究光，我们经常可以发现星星有多大，有多热，有多远，以及有多大质量。我们还可以获得关于表面层（星星的“大气层”）的更详细的信息，例如气体的密度，气体的化学成分是什么，以及气体是安静的还是像刮风的日子一样冒泡和吹。*** 我的总体研究计划集中在使用星光试图回答有关特定类型的恒星的具体问题。例如，一些恒星被观测到被强磁场所渗透。我正在观察一些恒星的磁场，这些恒星所处的环境使我们能够估计它们的年龄，并寻找这些恒星的平均磁性如何随着年龄的变化而变化的证据，从年轻的恒星到年老的恒星。研究这个问题应该有助于我们理解磁场是如何在恒星中增长和变化的。* 我的计划的另一个方面涉及在白色矮星中寻找非常弱的磁性。当像太阳这样的星星耗尽燃料并坍缩成一个与地球差不多大的“微小”天体时，就会产生这些炽热的恒星尸体，它们只是随着时间的推移而冷却。这将再次帮助我们更好地理解恒星的磁场。 * 我也在观察来自恒星的光，这些恒星非常年轻，它们周围仍然有一些气体，引力将它们聚集在一起形成新的星星。靠近星星但还没有落到表面的气体被来自新星星的光加热，并发光。通过分析这种发光现象，我们可以了解更多关于气体的信息--那里有多少物质，它有多热，等等。* 我的研究的每一个方面都是关于恒星的一个非常小的、具体的问题，但结果就像一个巨大的拼图游戏的碎片--把它们放在一起，我们就可以更好地理解恒星如何形成和在它们的生命中变化的大故事。