High-mass binaries - a unique laboratory to study the formation and evolution of stars and for measuring cosmic distances

高质量双星——研究恒星形成和演化以及测量宇宙距离的独特实验室

• 批准号: 426508932
• 负责人: Professor Dr. Rolf Chini
• 金额: --
• 依托单位: Nicolaus Copernicus Astronomical Center
• 依托单位国家: 德国
• 项目类别: Research Grants
• 财政年份: 2019
• 资助国家: 德国
• 起止时间: 2018-12-31 至 2022-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/426508932?language=en
• 关键词: mass; binaries; unique; laboratory; study

High-mass stars seem to have the highest multiplicity rate among all stars which increases the chance to be observed also as eclipsing binary (EB) systems. As a consequence early-type EBs are not only a unique laboratory to study properties, of high-mass stars but – due to their brightness – they have also the potential for measuring accurate distances to nearby galaxies, and thus to significantly improve the Hubble constant determination based on Cepheids and SN Ia.Our archive, containing about 3000 O- and 5000 B-star spectra, represents a solid – probably the largest – collection of homogeneous, multi-epoch, high S/N spectra for high-mass stars – among them about 80 SB2 systems in the range O3 – O9 and 90 SB2 systems in the range B0 – B9. Likewise, our multiband photometric Galactic Disk Survey of the southern Milky Way has produced high-precision light curves over a period of almost 10 years and revealed about 85,000 variable objects of which more than 85% were not known previously as variables. This photometric archive comprises 473 O and more than 1000 B stars – among them 41 O-type EBs and about 300 B-type EBs.With the present project we want to go into a detailed investigation of interesting objects by combining our high-quality EB light curves with our multi-epoch high-resolution spectra to attack the major questions with respect to high-mass stars, i.e.- Stellar parameters like mass, mass-ratio, luminosity, radius, abundances, period, etc.- Origin and evolution of close multiple and interacting systems - Detection and investigation of higher multiplicity systems- Mass transfer and rotation of individual components in multiple systemsApart from exploring stellar properties, detached double-lined spectroscopic EBs offer a unique opportunity to measure accurate distances to nearby galaxies. By high-precision V – K measurements of early-type EBs we will solve the main problem related to the calibration of the surface brightness – color relation technique making it an excellent tool for obtaining 2% distances to individual EB systems in a volume of 2 Mpc now, and up to 30 Mpc with the advent of future extremely large telescopes.During the present project we will measure 1.5 – 2% geometrical distances to two systems in M31, one system in M33 and one in IC 1613 and thus will significantly improve distance determinations to these galaxies based on the EBs.In particular we will calibrate the dependence of P-L relations of Cepheids on metallicity which will be a fundamental and necessary step towards a Hubble constant determination accurate to 1%.The combination of different expertizes of both teams will allow to exploit huge potential of binary systems to study both star formation and evolution, and improve the calibration of the extragalactic distance scale. The obtained results will have strong impact on many different fields of modern astrophysics: star formation, stellar evolution, studies of nearby galaxies and cosmology.

大质量恒星似乎在所有恒星中具有最高的多重性，这增加了被观测到的机会，也是食双星系统。因此，早期型EB不仅是研究大质量恒星性质的独特实验室，而且-由于它们的亮度-它们也有可能测量到附近星系的精确距离，从而显着改善基于造父变星和SN Ia的哈勃常数测定。我们的档案，包含大约3000个O-和5000个B-恒星光谱，代表了一个固体-可能是最大的-收集均匀，多时代，高S/N光谱的高质量恒星-其中约80 SB 2系统的范围O3 -O 9和90 SB 2系统的范围B 0-B 9。同样，我们对南银河系的多波段光度银河系盘调查在近10年的时间里产生了高精度的光变曲线，并揭示了大约85，000个可变物体，其中85%以上以前不知道是变量。这个测光档案包括473颗O星和1000多颗B星-其中有41颗O型EB和大约300颗B型EB。在本项目中，我们希望通过结合我们的高质量EB光变曲线和我们的多历元高分辨率光谱，对感兴趣的天体进行详细的研究，以解决与大质量恒星有关的主要问题，即-恒星参数，如质量、质量比、光度、半径、丰度、周期等。紧密多重和相互作用系统的起源和演化-更高多重性系统的探测和研究-多重系统中单个组件的质量传递和旋转除了探索恒星特性外，分离的双线光谱EB提供了一个独特的机会来测量到附近星系的精确距离。通过对早期型电子束的高精度V-K测量，我们将解决与表面亮度-颜色关系技术校准相关的主要问题，使其成为在2 Mpc的体积中获得单个电子束系统2%距离的优秀工具。随着未来超大型望远镜的出现，我们将测量到M31中两个系统的1.5 - 2%的几何距离，特别是我们将校准造父变星的P-L关系对金属丰度的依赖性，这将是实现哈勃常数精确到1%的基本和必要的一步这两个小组的不同专长相结合，将能够利用双星系统的巨大潜力来研究星星的形成和演化，并改进河外距离尺度的校准。这些结果将对现代天体物理学的许多不同领域产生重大影响：星星形成、恒星演化、邻近星系研究和宇宙学。