Evolution of Circumstellar Disks Surrounding Massive Stars

围绕大质量恒星的星周盘的演化

• 批准号: RGPIN-2022-04180
• 负责人: Jones, Carol
• 金额: $ 2.04万
• 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: 2022
• 资助国家: 加拿大
• 起止时间: 2022-01-01 至 2023-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=763016
• 关键词: Evolution; Circumstellar; Disks; Surrounding; Massive

Different types of disk-like distributions of gas, stars, and planets are found in the Universe. Our Sun is in a spiral arm within a disk-like distribution of stars, gas, and dust in our Galaxy. The Earth formed in a disk of material surrounding the Sun. Black holes have disks of material swirling about them, and there are many more examples of the ubiquity of such disks. Consequently, knowing how disks form and appreciating the processes operating in them are critical to understanding many objects in astrophysics. My research focuses on massive stars, in particular B-emission stars (Be stars), which are surrounded by gaseous disks. A variety of techniques are used to observe these remarkably bright objects, hundreds of which exist right in our Galaxy. Providing an ideal environment for studying disks, these stars can spew out one thousand times more energy per second than our Sun, and as a result they go through different stages in their lifetime more quickly. Since the disk is formed from gas launched from the star or gas from a binary companion, it is not shrouded in dust like disks in star forming regions, allowing for easier observing. The rotation rate of the star is also quite fast causing the materials inside the star to mix, affecting the star's production of energy and its lifespan. When a Be star reaches the end of its life and blows up as a supernova, it can trigger a new generation of stars, directly affecting the evolution of its surroundings. Despite decades of study, the fundamental question to be addressed in this field is why the disk forms and my research will tackle this important puzzle. I build computer models and use real observations to constrain my work. Rapid stellar rotation seems to be an essential ingredient, but something else must help to eject the material - perhaps, a pulsation on the stellar surface, a push from the radiation field or maybe the material is donated by a nearby companion. My research will allow these complex details to be sorted out. The star is the energy source for the disk. Starlight is scattered, reabsorbed, and polarized by the disk before we collect it with various techniques. Therefore, collected light has signatures from the star and disk, which gives lots of information. Distinct wavelengths of light come from different parts of the disk system where temperature and other conditions may be quite different. As such, my research will investigate the entire range of light (wavelengths) to understand all the different parts of the star/disk system. There is a long history of pioneering discipline-specific study and expertise in Canada, especially at Western University, of Be star disks. The results of my program will not only provide key results for understanding this type of disk but will help researchers worldwide apply the insight to better understand other types of disks, placing important constraints on the formation of massive stars and on the evolution of stars and galaxies.

在宇宙中发现了不同类型的气体、恒星和行星的盘状分布。我们的太阳位于银河系中恒星、气体和尘埃盘状分布的旋臂中。地球形成于围绕太阳的物质盘中。黑洞有物质盘围绕着它们旋转，还有更多的例子可以证明这种盘的普遍性。因此，了解盘的形成和理解其中的过程对于理解天体物理学中的许多对象至关重要。 我的研究重点是大质量恒星，特别是B发射星（Be星），它们被气体盘包围。各种技术被用来观察这些非常明亮的物体，其中数百个就存在于我们的银河系中。这些恒星提供了一个理想的环境来研究磁盘，它们每秒可以喷出比我们的太阳多一千倍的能量，因此它们在生命中更快地经历不同的阶段。由于这个圆盘是由从星星发射的气体或从双星伴星发射的气体形成的，所以它在星星形成区域并没有被尘埃一样的圆盘所笼罩，从而更容易观察。星星的自转速度也相当快，导致星星内部的物质混合，影响星星的能量生产和寿命。当一颗Be星星到达生命的尽头，爆炸成超新星时，它可以引发新一代的恒星，直接影响周围环境的演化。 尽管经过了几十年的研究，这个领域需要解决的基本问题是为什么磁盘形成，我的研究将解决这个重要的难题。我建立计算机模型，并使用真实的观察来约束我的工作。快速的恒星旋转似乎是一个必不可少的成分，但其他东西必须有助于喷射物质-也许，恒星表面的脉动，辐射场的推动，或者物质是由附近的同伴捐赠的。我的研究将使这些复杂的细节得到整理。星星是圆盘的能量源。在我们用各种技术收集星光之前，星光会被圆盘散射、重吸收和偏振。因此，收集的光具有来自星星和盘的特征，这提供了大量信息。不同波长的光来自磁盘系统的不同部分，那里的温度和其他条件可能完全不同。因此，我的研究将调查整个光（波长）范围，以了解星星/盘系统的所有不同部分。在加拿大，特别是在西方大学，Be星星盘的开创性学科研究和专业知识有着悠久的历史。我的计划的结果不仅将为理解这种类型的磁盘提供关键结果，而且将帮助世界各地的研究人员应用洞察力来更好地了解其他类型的磁盘，对大质量恒星的形成以及恒星和星系的演化施加重要限制。