论文标题
Gaia-enceladus Galaxy中的锂和铍
Lithium and Beryllium in the Gaia-Enceladus Galaxy
论文作者
论文摘要
来自Gaia Dr2和Apogee调查的数据显示，内部银河系中的一个相对较新的成分，这可能是一个名为Gaia-Enceladus的破坏矮星银河的动态残余，与大约10 Gyrs的银河系相撞。这项合并事件为研究矮星系中元素的化学丰度提供了一个非凡的机会，因为它们通常在外部星系中受到阻碍。在这里，我们专注于Li和成为矮星，这些恒星即使在当地的星系中也遥不可及。在Galah，Gaia-Eso调查中进行搜索，在文献中，我们发现了属于Gaia-Enceladus Galaxy的几个现有的7li丰度确定。低金属性末端的恒星的7li丰度与银河光环的恒星重叠。这些是有效的外乳乳外7li测量值，这表明{\ it It Spite Plateau}是普遍的，就像宇宙学LI一样。我们在101颗恒星中发现了一个富裕的巨人，这表明一小部分与银河系相似。我们还收集了9BE的大量，用于从文献中的25个Gaia-enceladus星星的子样本。它们的丰度在低金属末端共享银河[BE/H]值，但使用[Fe/H]的较慢，并显示出降低的分散体。这表明以银河系观察到的散射可以反映不同恒星成分的不同\ beix \进化模式，这些模式在银河系中混合了。
Data from Gaia DR2 and APOGEE surveys revealed a relatively new component in the inner Galactic halo, which is likely the dynamical remnant of a disrupted dwarf galaxy named Gaia-Enceladus that collided with the Milky Way about 10 Gyrs ago. This merging event offers an extraordinary opportunity to study chemical abundances of elements in a dwarf galaxy, since they are generally hampered in external galaxies. Here, we focus on Li and Be in dwarf stars which are out of reach even in Local Group galaxies.Searching in GALAH, Gaia-ESO survey and in literature, we found several existing 7Li abundance determinations of stars belonging to the Gaia-Enceladus galaxy. The 7Li abundances of stars at the low metallicity end overlap with those of the Galactic halo.These are effective extragalactic 7Li measurements, which suggest that the {\it Spite plateau} is universal, as is the cosmological Li problem. We found a Li-rich giant out of 101 stars, which suggests a small percentage similar to that of the Milky Way. We also collect 9Be abundances for a subsample of 25 Gaia-Enceladus stars from literature. Their abundances share the Galactic [Be/H] values at the low metallicity end but grow slower with [Fe/H] and show a reduced dispersion. This suggests that the scatter observed in the Milky Way could reflect the different \beix\ evolution patterns of different stellar components which are mixed-up in the Galactic halo.
