A Programme in Astrophysical Theory and Observations at Leeds

利兹天体物理理论和观测项目

• 批准号: ST/P00041X/1
• 负责人: Melvin Hoare
• 金额: $ 189.63万
• 依托单位: University of Leeds
• 依托单位国家: 英国
• 项目类别: Research Grant
• 财政年份: 2017
• 资助国家: 英国
• 起止时间: 2017 至 无数据
• 项目状态: 已结题
• 来源: https://gtr.ukri.org/projects?ref=ST%2FP00041X%2F1
• 关键词: Programme; Astrophysical; Theory; Observations; Leeds; Programme; Astrophysical; Theory; Observations; Leeds

This research programme principally addresses how stars and planets form from clouds of dust and gas.Stars form from the clouds of gas that occupy interstellar space and the small dust grains mixed in them. The clouds are highly filamentary and magnetic fields, that also pervade space, are likely to have had a role in shaping them, and controlling their collapse under gravity to form stars. We will conduct computer simulations to ascertain how the beginning of the formation of stars like our Sun takes place. The formation of stars much more massive than our Sun has proved to be much more problematic as they are rare and distant and produce prodigious amounts of radiation that blow material away rather than let it fall in. As the infalling material gets close in to the star we expect it to complete its journey in a thin disc orbiting the star. Detailed mapping of the molecular emission with the ALMA telescope is beginning to reveal these discs. We will significantly extend these initial discoveries and interpret the data with sophisticated models to find out how material flows into these discs. The rich spectra due to molecules at these wavelengths will be explored with novel data mining techniques to search for ways that we can trace changes over time as these stars form. The inner regions of these discs where the material completes its journey on to the forming star will be studied using the techniques of infrared interferometry. This reveals spatial information at levels 10 to 100 times better than the Hubble Space Telescope, where we may start to see the material being channelled by magnetic fields instead. At the same time that material is spiralling onto a star via a disc, some of it is being ejected at high speeds along the rotation axis, again most likely by magnetic fields. To follow these jets further out we will use the highly sensitive network of radio dishes in the UK, e-MERLIN, to map their emission. Comparison with complex models will show whether particles are being accelerated to relativistic speeds in these jets, further enhancing their potential impact on their environment.As massive stars finally begin to clear away the material from which they were born the combined effect of the winds driven by their strong radiation fields has a dramatic effect. As the winds slam into the molecular material and each other they get heated to millions of degrees and emit strongly in the X-ray region as observed with NASA's Chandra satellite. The most massive stars have such short lives of a few million years that they can blow up as supernovae whilst still surrounded by the remnants of the molecular clouds. Computer simulations will be used to tackle this problem to investigate how these processes can terminate the star formation episodes in giant molecular clouds. The discs that surround stars like the Sun as they are forming are the sites where planets form, built up from the coalescence of dust grains. This is only thought to occur in the quieter regions of the disc where turbulence due to the magnetic fields is less strong. We will perform calculations of the chemical effects that occur where the icy grains are sublimated that then affect their charge, and hence, magnetic properties. How the charged dust particles move relative to the gas is important in the formation process and that will be examined with sophisticated computer simulations. Near the end of the lives of stars, the very dust grains that begin the planet formation process are themselves produced. We will perform detailed chemical calculations to work out how these silicate minerals are built up from the gaseous elements in the rich, cool, atmospheres of giant stars. Many of these heavier elements themselves are first made in the exploding stars known as supernovae. We will perform state-of-the-art simulations of the thermo-nuclear detonation of these stars, and examine how this affects the production of elements in the cosmos.

该研究计划主要解决了恒星和行星如何从灰尘和气体云中形成。星星从占据星际空间的气体和中间的小尘土谷物中形成。云层是高度丝状和磁场，也遍布遍布空间，可能在塑造它们中起作用，并控制其在重力下塌陷以形成恒星。我们将进行计算机模拟，以确定像太阳这样的恒星形成的开始是如何发生的。事实证明，恒星的形成比我们的太阳更大得多，因为它们罕见，遥远，产生大量的辐射，这些辐射量吹走而不是让它掉入。随着输入的材料接近恒星，我们期望它在稀薄的圆盘上完成恒星的圆盘。用ALMA望远镜对分子发射的详细映射开始揭示这些光盘。我们将显着扩展这些初始发现，并使用复杂的模型来解释数据，以找出材料如何流入这些光盘。由于这些波长的分子而引起的丰富光谱将通过新型的数据挖掘技术探索，以搜索我们可以随着这些恒星形成的时间来追踪随时间变化的方式。这些圆盘的内部区域将使用红外干涉测量学技术来研究材料完成其前往成型恒星的旅程。这揭示了比哈勃太空望远镜高10到100倍的空间信息，在那里我们可能会开始看到磁场引导的材料。同时，材料正在通过圆盘螺旋螺旋式螺旋，其中一些是沿着旋转轴高速弹出的​​，同样，磁场很可能是由磁场弹出的。为了进一步遵循这些喷气机，我们将使用英国E-Merlin的高度敏感的无线电菜肴网络来绘制其排放量。与复杂模型的比较将表明颗粒是否正在加速到这些喷气机的相对速度，进一步增强了它们对环境的潜在影响。随着巨大的恒星最终开始清除其出生的材料，其强烈辐射场驱动的风的综合效应具有巨大的效果。随着风向分子材料猛撞，彼此之间被加热到数百万度，并在X射线区域强烈散发，如NASA的Chandra卫星所观察到的那样。最庞大的恒星经历了几百万年的短暂寿命，可以炸毁超新星，而仍然被分子云的残余物所包围。计算机模拟将用于解决此问题，以研究这些过程如何终止巨型分子云中的恒星形成事件。围绕星星像太阳一样形成的圆盘是由尘土谷物合并建立的行星形成的地点。人们认为这仅发生在磁盘的较安静区域中，因为磁场引起的湍流不太强。我们将对发生冰冷晶粒的升华，然后影响其电荷并因此，因此进行磁性特性进行计算。带电的灰尘颗粒相对于气体的移动方式在编队过程中很重要，并且将通过复杂的计算机模拟进行检查。在恒星生命的尽头，开始生产地球形成过程的尘土谷物本身就是生产的。我们将执行详细的化学计算，以确定这些硅酸盐矿物如何从巨型恒星的丰富，凉爽，氛围中的气态元素建立。这些较重的元素本身首先是在被称为超新星的爆炸恒星中制成的。我们将对这些恒星的热核爆炸进行最新的模拟，并检查这如何影响宇宙中元素的产生。