Multiplicity of stars as a function of mass

虽然通常认为大多数恒星都是以双星的形式形成的，但最近对低质量恒星的研究表明，M型、L型和T型矮星大多是单一的。由于在数量上占主导地位，这甚至导致了银河系中大多数燃烧氢的恒星都是单身的建议。然而，近年来观测的巨大进步也揭示了大约四分之一的恒星可能由更高级别的星星系统组成;这个比例被认为要高得多，如猎户座四边形中的大质量恒星所示。因此，等级多重数似乎是一般星星形成的一个重要组成部分，而恒星质量在多大程度上参与其中是一个关键问题。南部的样本包括所有（~ 250）O星的银河系O星的汇编，以及260 B和170 F/G星，都是由多历元光谱观测。北方的样本包括大约350颗附近的F-和G-型恒星，这些恒星已经获得了高分辨率的光谱。除了O星，所有的对象形式的公正和体积完整的样本取自依巴谷档案。从数据中，我们希望获得的分数SB 1和SB 2系统作为恒星质量的函数。我们打算确定恒星的光谱类型和/或基本恒星参数，并将这些数据与恒星的多重性、金属丰度和质量联系起来。

Although it is usually asserted that most stars form as binaries, more recent investigations on low-mass stars suggest that M-, L- and T-type dwarfs are mostly single. Being the dominant population by number, this has even led to the suggestion that the majority of all hydrogen-burning stars in the Milky Way Galaxy are single. However, the considerable observational progress in recent years has also brought to light that up to about one quarter of all stars may consist of higher level star systems; this fraction is believed to be even much higher as indicated by massive stars in the Orion Trapezium. Thus, hierarchical multiples appear to be an important part of general star formation and it is a key question to what extent the stellar mass is involved.It is proposed to investigate the multiplicity fraction for stars in the mass range of 0.8 - 100 M☉ based on about 1000 stars with high-resolution spectroscopy. The southern sample consists of all (~ 250) O stars from the compilation of Galactic O Stars as well as of 260 B and 170 F/G stars, all to be observed by multi-epoch spectroscopy. The northern sample comprises about 350 nearby F- and G-type stars where high-resolution spectra have already been taken. Apart from the O stars, all objects form unbiased and volume-complete samples taken from the Hipparcos archive.From the data we wish to obtain the fraction of the SB1 and SB2 systems as a function of stellar mass. We intend to determine the spectral types and/or the basic stellar parameters of the stars and shall relate these data in terms of the derived stellar multiplicities, metallicities and masses.