权益分类	功能权益	普通用户	{{item.name}}会员
{{category.name}}	{{benefitItem.name}}

The formation and evolution of stars

恒星的形成和演化

基本信息

批准号：
ST/F003277/1
负责人：
Matthew Bate
金额：
$ 120.03万
依托单位：
UNIVERSITY OF EXETER
依托单位国家：
英国
项目类别：
Research Grant
财政年份：
2008
资助国家：
英国
起止时间：
2008 至无数据
项目状态：
已结题

来源：
https://gtr.ukri.org/projects?ref=ST%2FF003277%2F1
关键词：
formation evolution stars

项目摘要

We propose to conduct research into the formation of stars and planets. Stars are born in galaxies, from giant clouds of dust and molecular gas. Our group is involved in several surveys of galactic star forming regions using the sub-millimetre waveband, and we will exploit these surveys to better understand the properties and evolution of the molecular clouds as they collapse under gravity to form stars. We also plan to study the properties of star forming clusters, using statistical analyses of the colour and luminosities of the stars in comparison with models in order to determine cluster ages and, subsequently, to map the progress of star formation as a function of position and time within our Galaxy. What are the necessary conditions for planets to form in the dusty disks around protostars? This question will be addressed using multiwavelength (from the optical, through the infrared, to the sub-millimetre) observations of individual objects combined with supercomputer simulations of the dynamics of - and passage of light through - the disks. This research will tell us how the dust properties inside the disks change as grain growth occurs. We will examine the dynamics of vertical and radial mixing within disks, and how processed grains are transported from the inner disk to the outer disk. The radial mixing may be the result of protostellar outflows, and we will critically examine how the material from the disk is accreted onto the stars, and why a significant fraction of this material is ejected from the system. The disks outlined above are the birth place of planets. We now know of over 250 planets outside our own solar system - the exoplanets. We propose to use two techniques to search for new systems, and to directly image planets around other stars. We will find new planets using the transit technique, in which the exoplanet passes in front of its parent star, which we observe as a dip in its brightness. Imaging planets around other stars is an extraordinarily difficult task, principally due to the enormous contrast between the bright star and the dim planet. We are proposing to use a new instrument which will allow us, for the first time, to image these distant worlds and measure their atmospheric properties. On the largest scales we wish to use observations to probe star formation at the earliest stages of the Universe. This work requires imaging and spectroscopy using the world's largest telescopes, and involves attempting to find the most distant galaxies in the Universe, which are in turn the youngest (less than 10% of the age of local galaxies). We will use these observations to determine the epoch at which the Universe was reionized by the first stars.

我们建议对恒星和行星的形成进行研究。恒星诞生于星系中，由巨大的尘埃和分子气体云构成。我们小组参与了几次使用亚毫米波段对银河系恒星形成区域的调查，我们将利用这些调查来更好地了解分子云在重力下坍塌形成恒星时的性质和演化。我们还计划研究恒星形成星团的性质，利用对恒星的颜色和光度的统计分析，并与模型进行比较，以便确定星团年龄，并随后绘制恒星形成过程随我们银河系内位置和时间的函数图。行星在原恒星周围尘土飞扬的圆盘中形成的必要条件是什么？这个问题将通过对单个物体的多波长(从光学的、通过红外的、到亚毫米的)观测，结合超级计算机对光盘的动力学和通过光盘的光的模拟来解决。这项研究将告诉我们，随着颗粒的生长，圆盘内的尘埃性质是如何变化的。我们将研究圆盘内垂直和径向混合的动力学，以及加工后的颗粒如何从内部圆盘输送到外部圆盘。径向混合可能是原恒星外流的结果，我们将批判性地研究盘中的物质是如何吸积到恒星上的，以及为什么这种物质的很大一部分被从系统中喷出。上面勾勒出的圆盘是行星的诞生地。我们现在知道太阳系外有250多颗行星--系外行星。我们建议使用两种技术来搜索新的系统，并直接为其他恒星周围的行星成像。我们将使用凌日技术发现新的行星，在凌日技术中，系外行星从其母恒星前面经过，我们观察到其亮度下降。为其他恒星周围的行星成像是一项异常困难的任务，主要是因为明亮的恒星和昏暗的行星之间存在巨大的对比。我们正在提议使用一种新的仪器，这将使我们第一次能够成像这些遥远的星球并测量它们的大气特性。在最大的尺度上，我们希望利用观测来探测宇宙最早阶段的恒星形成。这项工作需要使用世界上最大的望远镜进行成像和光谱分析，并试图找到宇宙中最遥远的星系，而这些星系又是最年轻的(不到当地星系年龄的10%)。我们将利用这些观测来确定宇宙被第一批恒星重新电离的时代。