论文标题
第一个R-Process增强恒星被证实是银河凸起的成员
The first r-process enhanced star confirmed to be a member of the Galactic bulge
论文作者
论文摘要
目标。具有强大增强R的恒星是罕见的,并且通常具有金属贫困,通常具有[Fe/H] <-2 dex,并且在Halo中发现。在这项工作中,我们旨在调查一个候选R-Process富含膨胀恒星,其金属性相对较高的金属性为-0.65 DEX,并将其与先前发表的RICH候选恒星进行比较。方法。我们使用来自先前五个以前的五个不同研究的恒星参数,重新考虑了红色巨星2MASS J18082459-254444的高分辨率光谱的丰度分析,并确定其欧洲群(EU)和钼(MO)丰度。应用2个质量光度法,GAIA星形统和运动学,我们估计距离,轨道和人口成员的2MASS J18082459-2548444,以及先前报道的R- EN-EN-EN-ENCH 2MASS 2MASS J18174532-3353235。结果。我们发现2MASS J18082459-2548444是一款相对富含金属的R-Process Star,在欧盟和MO中得到增强,但在S过程中并未显着增强。它具有基于距离和轨道的银河凸起中成员资格的较高可能性。我们发现,即使2MASS J18174532-3353235在金属性较低的情况下,这两个恒星都显示出升高的[EU/FE]值的R过程增强。此外,我们发现2MASS J18174532-3353235可能具有光环或厚度厚的圆盘起源。结论。我们得出的结论是,2MASS J18082459-2548444代表了局限于内部凸起的确认的R-Process增强恒星的第一个例子,这可能是与棒形成相关的富集时期的遗物。
Aims. Stars with strong enhancements of r-process elements are rare and tend to be metal-poor, with generally [Fe/H] <-2 dex and found in the halo. In this work we aim to investigate a candidate r-process enriched bulge star with a relatively high metallicity of -0.65 dex, and compare it with a previously published r-rich candidate star in the bulge. Methods. We reconsider the abundance analysis of a high-resolution optical spectrum of the red-giant star 2MASS J18082459-2548444 and determine its europium (Eu) and molybdenum (Mo) abundance, using stellar parameters from five different previous studies. Applying 2MASS photometry, Gaia astrometry and kinematics, we estimate distance, orbits, and population membership of 2MASS J18082459-2548444 and a previously reported r-enriched star 2MASS J18174532-3353235. Results. We find that 2MASS J18082459-2548444 is a relatively metal rich enriched r-process star that is enhanced in Eu and Mo but not substantially enhanced in s-process elements. It has a high probability of membership in the Galactic bulge based on its distance and orbit. We find that both stars show r-process enhancement with elevated [Eu/Fe]-values, even though 2MASS J18174532-3353235 is 1 dex lower in metallicity. Additionally, we find that 2MASS J18174532-3353235 plausibly has a halo or thick disc origin. Conclusions. We conclude that 2MASS J18082459-2548444 represents the first example of a confirmed r-process enhanced star confined to the inner bulge, possibly a relic from a period of enrichment associated with the formation of the bar.