Hyper-velocity stars

超高速恒星

• 批准号: 33360260
• 负责人: Professor Dr. Ulrich Heber
• 金额: --
• 依托单位: Dr. Remeis-Sternwarte Bamberg - Astronomisches Institut -
• 依托单位国家: 德国
• 项目类别: Research Grants
• 财政年份: 2006
• 资助国家: 德国
• 起止时间: 2005-12-31 至 2016-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/33360260?language=en
• 关键词: Hyper; velocity; stars

We propose to study the newly discovered population of hyper-velocity stars in order to determine their true nature. Hyper-velocity stars move so fast that dynamical ejection from a massive black hole (as found e.g. in the Galactic centre) is their only suggested origin and they are becoming more and more recognized as an important tool to understand the history, nature and environment of massive black holes. Moreover, they travel with such extreme velocities that they are unbound to our Galaxy. Although the first hyper-velocity star was discovered only by 2005, already eight additional stars have been found recently (including 4 discoveries by our team) at distances as large as 20 to 110 kpc. We shall embark on a systematic search for candidate hyper-velocity blue stars to be drawn from the Sloan Digital Sky and Hamburg Surveys. Quantitative spectral analyses of high resolution spectra are required to clarify their evolutionary status (young massive or old low mass star) and their age as well as to measure the radial velocity and distance. Astrometry will be carried out to measure the proper motions. From the space motions the stellar path through the Galactic halo will be reconstructed. Although the stars unbound to the Galaxy are most spectacular, young hyper-velocity stars bound to the Galaxy are important to constrain the ejection mechanism, while such stars of large age are probes of the Galactic potential that can be used to constrain the Galactic escape velocity and the mass of the Galaxy.

我们建议研究新发现的超高速恒星群，以确定它们的真实性质。超高速恒星运动如此之快，以至于从大质量黑洞(例如在银河系中心发现的)的动力学抛射是它们唯一被认为是起源的，它们越来越多地被认为是理解大质量黑洞的历史、性质和环境的重要工具。此外，它们以极高的速度行进，不受我们银河系的束缚。虽然第一颗超高速恒星直到2005年才被发现，但最近已经发现了另外8颗恒星(包括我们团队发现的4颗)，距离达到20到110kpc。我们将开始从斯隆数字天空和汉堡探测中系统地寻找候选的超高速蓝色恒星。需要对高分辨率光谱进行定量光谱分析，以澄清它们的演化状态(年轻的、大质量的或年老的低质量恒星)和它们的年龄，以及测量径向速度和距离。将进行天体测量来测量自身运动。从空间运动中，将重建通过银河晕的恒星路径。虽然没有与银河系结合的恒星最为壮观，但与银河系结合的年轻超高速恒星对于约束抛射机制非常重要，而这类年龄较大的恒星是银河系潜力的探测器，可以用来约束银河系的逃逸速度和质量。