Recently , a new cylindrical-shaped stream of stars up to 700 pc long was discovered hiding in the Galactic disk using kinematic data enabled by the Gaia mission .
This curious stream of stars , dubbed the Psc–Eri stream , was initially thought to be as old as 1 Gyr , yet its stars shared a rotation period distribution consistent with the 120-Myr-old Pleiades cluster .
In this work , we explore the detailed chemical nature of this stellar stream .
We carried out high-resolution spectroscopic follow-up of 42 Psc–Eri stream 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 ) , \alpha ( Mg , Si , Ca , Ti ) , Fe-peak ( Cr , Mn , Fe , Co , Ni , Zn ) , and neutron capture ( Sr , Y , Zr , Ba , La , Nd , Eu ) elements across 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 ( 0.04 dex when outliers are excluded ) .
We also find that ( 3 ) the abundance of Li indicates that Psc–Eri is \sim 120 Myr old , consistent with the gyrochronology result .
We find that ( 4 ) the stream has a [ X/Fe ] abundance spreads of 0.06 < \sigma [ X/Fe ] < 0.20 dex in most elements , and ( 5 ) no significant abundance gradients across its major axis except a potentially weak gradient in [ Si/Fe ] .
These results together show that the Psc–Eri stream is a uniquely close , young , chemically interesting laboratory for testing our understanding of star and planet formation .