论文标题
具有中子捕获元件的银河盘的富集：GD，DY和TH
Enrichment of the Galactic disc with neutron-capture elements: Gd, Dy, and Th
论文作者
论文摘要
对重元素起源的研究是核天体物理学的主要目标之一。在本文中，我们介绍了重$ r $ $ - 过程元素gadolinium（GD，Z = 64），dysprosium（DY，Z = 66）和Thorium（Th，Z = 90）的新观察数据，以276个银河系碟片（-1.0 $ <$ <$ <$ <$ <$ <$+0.3）。恒星光谱的高分辨率为42,000和75,000，信噪比高于100。通过比较三个GD线（149星）的观察到的GD，DY和TH的LTE丰度，而不是4019.13 a（170 Stars）（170颗恒星）。首次测量了样品GD和DY中约70％的恒星，而恒星的恒星则为95％。典型错误从0.07到0.16 DEX不等。本文以银河系光盘提供了第一组扩展的TH观测值。与我们先前研究中的Europium（EU，Z = 63）数据一起，我们将这些新观察结果与核合成预测和银河化学演化模拟进行了比较。我们确认[GD/FE]和[DY/FE]表现出相同的欧盟行为。我们使用GCE模拟研究了[Th/fe]与[EU/FE]相比的演变，表明与欧盟在银河系中唯一的R过程来源或富含TH的R-Process源的频率随[Fe/H]的增加而降低，这与欧盟不同的是金属性取决于金属性。
The study of the origin of heavy elements is one of the main goals of nuclear astrophysics. In this paper, we present new observational data for the heavy $r$-process elements gadolinium (Gd, Z=64), dysprosium (Dy, Z=66) and thorium (Th, Z=90) in a sample of 276 Galactic disc stars ( --1.0$<$[Fe/H]$<$+0.3). The stellar spectra have a high resolution of 42,000 and 75,000, and the signal-to-noise ratio higher than 100. The LTE abundances of Gd, Dy and Th have been determined by comparing the observed and synthetic spectra for three Gd lines (149 stars), four Dy lines (152 stars) and the Th line at 4019.13 A (170 stars). For about 70% of the stars in our sample Gd and Dy are measured for the first time, and Th for 95% of the stars. Typical errors vary from 0.07 to 0.16 dex. This paper provides the first extended set of Th observations in the Milky Way disc. Together with europium (Eu, Z = 63) data from our previous studies, we have compared these new observations with nucleosynthesis predictions and Galactic Chemical Evolution simulations. We confirm that [Gd/Fe] and [Dy/Fe] show the same behavior of Eu. We study with GCE simulations the evolution of [Th/Fe] in comparison with [Eu/Fe], showing that unlike Eu either the Th production is metallicity dependent in case of a unique source of the r-process in the Galaxy, or the frequency of the Th-rich r-process source is decreasing with the increasing of [Fe/H].
