The chemical nature of the young 120-Myr-old nearby Pisces–Eridanus stellar stream flowing through the Galactic disc
The chemical nature of the young 120-Myr-old nearby Pisces–Eridanus stellar stream flowing through the Galactic disc
复制标题
DOI：
10.1093/mnras/staa1673
复制
发表时间：
2020-03
影响因子：
4.8
通讯作者：
K. Hawkins;M. Lucey;J. Curtis
中科院分区：
文献类型：
--
作者：
K. Hawkins;M. Lucey;J. Curtis
最近，利用盖亚使命提供的运动学数据，在银河系圆盘中发现了一个长达700 pc的新的圆柱形恒星流。这个恒星流被称为双鱼座-波江座（Psc-Eri），最初被认为是1 Gyr，但它的恒星共享的旋转周期分布与1.2亿年前的人口一致。在这里，我们探索这个恒星流的详细化学性质。我们进行了高分辨率的光谱跟踪的42 Psc-Eri星使用麦克唐纳天文台，并结合这些数据与低分辨率LAMOST光谱调查观察到的40名成员的信息。总之，这些数据使我们能够测量轻/奇Z（Li，Na，Al，Sc，V），α（Mg，Si，Ca，Ti），Fe峰（Cr，Mn，Fe，Co，Ni，Zn）和中子捕获（Sr，Y，Zr，Ba，La，Nd，Eu）元素沿沿着Psc-Eri流的丰度分布。我们发现，该流是（1）近太阳的金属丰度与[Fe/H] = -0.03 dex和（2）有一个金属丰度的蔓延为0.07 dex（或0.04 dex时，排除异常值）。我们还发现（3）Li的丰度表明Psc-Eri的年龄为1.2亿年，与其陀螺年代学年龄相一致。此外，Psc-Eri的[X/Fe]丰度分布刚好大于大多数元素的典型不确定性，（5）它是一个外边缘围绕中心旋转的圆柱状系统，（6）除了[Si/Fe]中潜在的弱梯度外，沿其主轴沿着没有显著的丰度梯度。这些结果表明，Psc-Eri是一个独特的年轻化学实验室，可以测试我们对星星和行星形成的理解。
Recently, a new cylindrical-shaped stream of stars up to 700 pc long was discovered hiding in the Galactic disc using kinematic data enabled by the Gaia mission. This stream of stars, dubbed Pisces–Eridanus (Psc–Eri), was initially thought to be as old as 1 Gyr, yet its stars shared a rotation period distribution consistent with a population that was 120 Myr old. Here, we explore the detailed chemical nature of this stellar stream. We carried out high-resolution spectroscopic follow-up of 42 Psc–Eri stars using McDonald Observatory and combined these data with information for 40 members observed with the low-resolution LAMOST spectroscopic survey. Together, these data enabled us to measure the abundance distribution of light/odd-Z (Li, Na, Al, Sc, V), α (Mg, Si, Ca, Ti), Fe-peak (Cr, Mn, Fe, Co, Ni, Zn), and neutron capture (Sr, Y, Zr, Ba, La, Nd, Eu) elements along the Psc–Eri stream. We find that the stream is (1) near-solar metallicity with [Fe/H] = –0.03 dex and (2) has a metallicity spread of 0.07 dex (or 0.04 dex when outliers are excluded). We also find that (3) the abundance of Li indicates that Psc–Eri is ∼120 Myr old, consistent with its gyrochronology age. Additionally, Psc–Eri has (4) [X/Fe] abundance spreads that are just larger than the typical uncertainty in most elements, (5) it is a cylindrical-like system whose outer edges rotate about the centre, and (6) no significant abundance gradients along its major axis except a potentially weak gradient in [Si/Fe]. These results show that Psc–Eri is a uniquely close young chemically interesting laboratory for testing our understanding of star and planet formation.