论文标题
R-Process Alliance：Rave J183013.5-455510的特殊化学丰度模式
The R-Process Alliance: The Peculiar Chemical Abundance Pattern of RAVE J183013.5-455510
论文作者
论文摘要
我们报告了Rave J183013.5-455510的光谱分析，这是一颗极为金属贫困的恒星，在CNO中高度增强，并且具有快速中子捕获过程的贡献。这个对象没有二进制的证据。在[fe/h] = -3.57时，这是当前观察到的金属恒星之一，中子捕获元件的丰富度有18个。在太阳系R-Process预测之上的BA，LA和CE丰度的存在表明，必须有一个非标准的R-Process元素来源，以如此低的金属性运行。一个合理的解释是，这种增强性源自中子星级合并事件中异常快速速度的材料。我们还探讨了中子捕获元件在旋转巨大恒星的进化和爆炸过程中产生的可能性。此外，基于与零金属性微弱超新星产量的比较，我们推测Rave J1830-4555是由两种祖细胞类型预先富含的气云形成的。从基于GAIA DR2测量值的分析中，我们表明该恒星具有类似于银河金属螺旋厚的恒星种群的轨道特性。
We report on the spectroscopic analysis of RAVE J183013.5-455510, an extremely metal-poor star, highly enhanced in CNO, and with discernible contributions from the rapid neutron-capture process. There is no evidence of binarity for this object. At [Fe/H]=-3.57, this is one of the lowest metallicity stars currently observed, with 18 measured abundances of neutron-capture elements. The presence of Ba, La, and Ce abundances above the Solar System r-process predictions suggest that there must have been a non-standard source of r-process elements operating at such low metallicities. One plausible explanation is that this enhancement originates from material ejected at unusually fast velocities in a neutron star merger event. We also explore the possibility that the neutron-capture elements were produced during the evolution and explosion of a rotating massive star. In addition, based on comparisons with yields from zero-metallicity faint supernova, we speculate that RAVE J1830-4555 was formed from a gas cloud pre-enriched by both progenitor types. From analysis based on Gaia DR2 measurements, we show that this star has orbital properties similar to the Galactic metal-weak thick-disk stellar population.
