ASTThe Formation and Dynamics of Star Clusters

AST星团的形成和动力学

• 批准号: ST/M005569/1
• 负责人: Nicholas Wright
• 金额: $ 52.74万
• 依托单位: Keele University
• 依托单位国家: 英国
• 项目类别: Fellowship
• 财政年份: 2015
• 资助国家: 英国
• 起止时间: 2015 至 无数据
• 项目状态: 已结题
• 来源: https://gtr.ukri.org/projects?ref=ST%2FM005569%2F1
• 关键词: ASTThe; Formation; Dynamics; Star; Clusters

One of the major questions astronomers currently face is "how do stars form?" Our own Sun is one of billions of stars that have formed in the 13-billion year lifetime of our Galaxy. When we look at these stars we see a wide range of sizes, masses and temperatures. Some stars appear isolated, others live in a binary system with another star, and some are found in groups of stars known as clusters. We think that the majority of stars form in clusters of various sizes, but recent observations have thrown doubt on this theory. By studying these groups we hope to better understand how stars and star clusters form with the wide range of properties that we see, and how this impacts the formation of planets around these stars, such as our own Earth.So far astronomers have relied upon information from a single snapshot in time to study star clusters. This is because many astrophysical processes take millennia to occur and it is impossible to observe these processes from start to finish. While we can learn a lot about star clusters from a single snapshot (such as the number of stars in them, their total mass and age) there is a critical ingredient missing: the motions of the stars. If we can measure how the individual stars in clusters are moving, we can work out using computer simulations what the cluster might have looked like a few million years ago, and how it will continue to develop in the future. This can be important when we want to understand the structure of star clusters and whether they are expanding or collapsing.There are two ways to measure the motions of stars in clusters. To measure the motions of stars coming towards us we use a spectrum of the light emitted by the star and measure the change in the position of spectral lines that shift according to a process known as the Doppler effect. This is the same process that changes the pitch of a siren when a fire engine travels towards you and then away from you. To measure the velocities of stars moving transversely we study images of the star separated by many years to see how the stars move relative to more stationary background stars. This is painstaking and detailed work - at the distances of these stars their transverse velocities of a few km/s are equivalent to being able to measure the rate of someone's hair growth on the International Space Station while you yourself are stood on the surface of the Earth!My goal is use these measurements for hundreds of young stars in many different star forming regions and star clusters to understand whether these regions are expanding or collapsing and what physical mechanisms are driving these processes. This is somewhat like being at a disco, but not being able to hear the music. By watching people dance it can be possible to work out what song is playing. The same is true for star clusters: by studying the dance of the stars we can work out what physical mechanisms are at work.What excites me about this area is the feeling that we are just now entering a new phase of exploration. Throughout the entire history of astronomy the vast majority of stars and galaxies have been static, never changing and never moving. Recent advances in detector technology and computer science combined with multi-national investment in new facilities such as the Gaia satellite and the Gaia-ESO Survey will transform our view of the sky and show us how the heavens change over time. At last we are overcoming our static view and can see the dance of the stars for the first time. For young researchers like myself, there awaits a treasure-trove of new discoveries. My project will put me at the forefront of this new era of exploitation.

天文学家目前面临的一个主要问题是“恒星是如何形成的？”我们的太阳是银河系130亿年生命中形成的数十亿颗恒星中的一颗。当我们观察这些恒星时，我们可以看到大小、质量和温度的大小不一。一些恒星看起来是孤立的，另一些与另一颗恒星生活在一个双星系统中，还有一些是在被称为星团的恒星群中发现的。我们认为大多数恒星都是在不同大小的星团中形成的，但最近的观测结果对这一理论提出了质疑。通过研究这些群，我们希望更好地了解恒星和星团是如何形成的，以及这是如何影响这些恒星周围行星的形成的，比如我们自己的地球。到目前为止，天文学家一直依靠一张及时的快照信息来研究星团。这是因为许多天体物理过程需要几千年的时间才能发生，而且不可能从头到尾观察到这些过程。虽然我们可以从一张快照中了解到许多关于星团的信息(例如其中的恒星数量、它们的总质量和年龄)，但我们缺少一个关键因素：恒星的运动。如果我们可以测量星系团中的单个恒星是如何运动的，我们就可以使用计算机模拟来计算出这个星系团在几百万年前可能是什么样子，以及它未来将如何继续发展。当我们想要了解星团的结构以及它们是在膨胀还是在坍塌时，这一点可能很重要。有两种方法可以测量星团中恒星的运动。为了测量向我们靠近的恒星的运动，我们使用恒星发出的光的光谱，并测量光谱线位置的变化，这些谱线根据一种称为多普勒效应的过程移动。当消防车朝你驶来，然后离开你时，这与改变警报器的音调是相同的过程。为了测量恒星横向运动的速度，我们研究了相隔多年的恒星的图像，以了解恒星相对于静止的背景恒星是如何运动的。这是一项艰苦而细致的工作--在这些恒星的距离上，它们几公里的横向速度/S相当于当你自己站在地球表面时，能够测量到国际空间站上某人的头发生长速度！我的目标是用这些测量结果来测量许多不同恒星形成区域和星团中的成百上千颗年轻恒星，以了解这些区域是在膨胀还是在坍塌，以及是什么物理机制在推动这些过程。这有点像是在迪斯科舞厅，但听不到音乐。通过观看人们跳舞，就有可能弄清楚正在播放的是哪首歌。星团也是如此：通过研究恒星的舞蹈，我们可以弄清楚是什么物理机制在起作用。这一领域让我兴奋的是，我们刚刚进入了一个新的探索阶段。纵观整个天文学历史，绝大多数恒星和星系都是静止的，从未改变，也从未移动过。探测器技术和计算机科学的最新进展，加上多国对新设施的投资，如盖亚卫星和盖亚-欧洲南方天文台调查，将改变我们对天空的看法，并向我们展示天空是如何随着时间的推移而变化的。终于，我们克服了静止的视野，第一次看到了星星的舞蹈。对于像我这样的年轻研究人员来说，等待着的是一大批新发现。我的项目将把我带到这个剥削的新时代的前沿。

项目成果

Massive stars in the hinterland of the young cluster, Westerlund 2

• DOI: 10.1093/mnras/sty1905
• 发表时间: 2018-07
• 期刊: Monthly Notices of the Royal Astronomical Society
• 影响因子: 4.8
• 作者: J. Drew;A. Herrero;A. Herrero;M. Mohr-Smith;M. Monguió;N. Wright;T. Kupfer;T. Kupfer;R. Napiwotzki

The velocity structure of Cygnus OB2

Cygnus OB2 的速度结构

• DOI: 10.48550/arxiv.2005.10260
• 发表时间: 2020
• 作者: Arnold B

Diffuse X-Ray Emission in the Cygnus OB2 Association

Cygnus OB2 协会中的漫射 X 射线发射

• DOI: 10.3847/1538-4365/acdd65
• 发表时间: 2023
• 期刊: The Astrophysical Journal Supplement Series
• 作者: Albacete-Colombo J

Proper motions of OB stars in the far Carina Arm

远船底座臂中 OB 星的自行运动

• DOI: 10.1093/mnras/stab2905
• 发表时间: 2021
• 期刊: Monthly Notices of the Royal Astronomical Society
• 影响因子: 4.8
• 作者: Drew J

The O star hinterland of the Galactic starburst, NGC 3603

银河星爆发的 O 星腹地，NGC 3603

• DOI: 10.48550/arxiv.1903.09053
• 发表时间: 2019
• 作者: Drew J