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

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.

这个研究计划主要探讨恒星和行星如何由尘埃和气体云形成。恒星是由占据星际空间的气体云和混合在其中的小尘埃颗粒形成的。这些云是高度可移动的，磁场也弥漫在太空中，很可能在塑造它们的过程中发挥了作用，并控制它们在重力作用下坍塌形成恒星。我们将进行计算机模拟，以确定像我们的太阳这样的恒星是如何形成的。比我们的太阳质量大得多的恒星的形成被证明是更有问题的，因为它们是罕见的和遥远的，并产生大量的辐射，吹走物质，而不是让它落入。当下落的物质接近星星时，我们预计它将在一个围绕星星旋转的薄圆盘中完成它的旅程。用阿尔马望远镜对分子发射的详细测绘开始揭示这些圆盘。我们将大大扩展这些最初的发现，并用复杂的模型解释数据，以找出物质如何流入这些圆盘。由于这些波长的分子而产生的丰富光谱将用新的数据挖掘技术来探索，以寻找我们可以追踪这些恒星形成时随时间变化的方法。这些圆盘的内部区域是物质完成其到形成中的星星的旅程的地方，将使用红外干涉测量技术进行研究。这比哈勃太空望远镜更好地揭示了10到100倍的空间信息，在那里我们可能会开始看到物质被磁场引导。在物质通过圆盘螺旋式地落在星星上的同时，其中一些物质也很可能是被磁场沿着旋转轴高速喷射出来的。为了进一步跟踪这些喷气式飞机，我们将使用英国高度敏感的无线电碟形天线网络e-MERLIN来绘制它们的排放。通过与复杂模型的比较，我们可以看到这些喷流中的粒子是否被加速到相对论速度，从而进一步增强了它们对周围环境的潜在影响。当大质量恒星最终开始清除它们诞生的物质时，它们强大的辐射场驱动的风的综合效应产生了戏剧性的影响。当风猛烈地撞击分子物质并相互撞击时，它们被加热到数百万度，并在X射线区域发出强烈的辐射，这是美国宇航局钱德拉卫星观测到的。最大质量的恒星只有几百万年的短暂寿命，它们可以爆炸成超新星，同时仍然被分子云的残余物所包围。计算机模拟将被用来解决这个问题，以研究这些过程如何终止巨型分子云中的星星形成事件。在恒星形成的过程中，围绕着太阳这样的恒星的圆盘是行星形成的场所，是由尘埃颗粒聚结而成的。这只被认为发生在圆盘的安静区域，那里由于磁场引起的湍流不太强烈。我们将计算冰颗粒升华时发生的化学效应，这些化学效应会影响它们的电荷，从而影响磁性。带电尘埃粒子如何相对于气体移动在形成过程中很重要，这将通过复杂的计算机模拟来研究。在恒星生命的末期，行星形成过程的开始的尘埃颗粒本身就产生了。我们将进行详细的化学计算，以弄清楚这些硅酸盐矿物是如何从巨大恒星的丰富，凉爽的大气中的气态元素中形成的。许多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形成的。我们将对这些恒星的热核爆炸进行最先进的模拟，并研究这如何影响宇宙中元素的产生。

项目成果

A statistical spectropolarimetric study of Herbig Ae/Be stars

Herbig Ae/Be 星的统计光谱偏振研究

• DOI: 10.1093/mnras/stx1891
• 发表时间: 2017
• 期刊: Monthly Notices of the Royal Astronomical Society
• 影响因子: 4.8
• 作者: Ababakr K

Numerical modelling of steady detonations with the CREST reactive burn model

使用 CREST 反应燃烧模型对稳定爆炸进行数值模拟

• DOI: 10.1007/s10665-019-09997-3
• 发表时间: 2019
• 期刊: Journal of Engineering Mathematics
• 影响因子: 1.3
• 作者: Cartwright M

IRAS 23385+6053: an embedded massive cluster in the making

• DOI: 10.1051/0004-6361/201935506
• 发表时间: 2019-05
• 期刊: Astronomy & Astrophysics
• 影响因子: 6.5
• 作者: R. Cesaroni;H. Beuther;A. Ahmadi;M. Beltrán;T. Csengeri;R. Galván-Madrid;C. Gieser;T. Henning;K. Johnston;P. Klaassen;R. Kuiper;S. Leurini;H. Linz;S. Longmore;S. Lumsden;L. Maud;L. Moscadelli;J. Mottram;A. Palau;T. Peters;R. Pudritz;Á. Sánchez-Monge;P. Schilke;D. Semenov;S. Suri;J. Urquhart;J. Winters;Qizhou Zhang;H. Zinnecker

The spatial evolution of young massive clusters II. Looking for imprints of star formation in NGC 2264 with Gaia DR2

年轻大质量星团的空间演化II.

• DOI: 10.1051/0004-6361/201936935
• 发表时间: 2020
• 期刊: Astronomy & Astrophysics
• 影响因子: 6.5
• 作者: Buckner A

Accelerating infall and rotational spin-up in the hot molecular core G31.41+0.31

• DOI: 10.1051/0004-6361/201832811
• 发表时间: 2018-03
• 期刊: Astronomy & Astrophysics
• 影响因子: 6.5
• 作者: M. Beltr'an;R. Cesaroni;V. Rivilla;'A. S'anchez-Monge;L. Moscadelli;A. Ahmadi;V. Allen;H. Beuther;S. Etoka;D. Galli;R. Galv'an-Madrid;C. Goddi;K. Johnston;A. Kolligan;R. Kuiper;M. Kumar;L. Maud;J. Mottram;T. Peters;P. Schilke;L. Testi;F. V. D. Tak;C. F. I. A. D. Arcetri;I. Institut;U. Koln;M. F. Astronomy;Heidelberg;K. Institute;U. Groningen;S. I. F. S. Research-S.-I.-F.-S.-Research-152214217;Groningen;J. B. C. F. Astrophysics;Manchester;Instituto de Radioastronom'ia y Astrof'isica Morelia-Instituto-de-Radioastronom'ia-y-Astrof'isica-2230372164;Department of AstrophysicsIMAPP;R. University;A. Observatory;Leiden University;S. O. Physics;Astronomy;Leeds;UK Astronomy Technology Centre;Royal Observatory of Edinburgh;I. O. Astronomy;Astrophysics;U. Tubingen;I. D. A. E. C. D. Espacco-I.-D.-A.-E.-C.-D.-Espacco-88742463;U. Porto;Centre for Gravitational Astrophysics;U. Hertfordshire;L. Observatory;M. F. Astrophysik;Garching;Eső