SIMBAD references

2021MNRAS.500..889A - Mon. Not. R. Astron. Soc., 500, 889-910 (2021/January-1)

The S2 stream: the shreds of a primitive dwarf galaxy.

AGUADO D.S., MYEONG G.C., BELOKUROV V., EVANS N.W., KOPOSOV S.E., ALLENDE PRIETO C., LANFRANCHI G.A., MATTEUCCI F., SHETRONE M., SBORDONE L., NAVARRETE C., GONZALEZ HERNANDEZ J.I., CHANAME J., PERALTA DE ARRIBA L. and YUAN Z.

Abstract (from CDS):

The S2 stream is a kinematically cold stream that is plunging downwards through the Galactic disc. It may be part of a hotter and more diffuse structure called the Helmi stream. We present a multi-instrument chemical analysis of the stars in the metal-poor S2 stream using both high- and low-resolution spectroscopy, complemented with a re-analysis of the archival data to give a total sample of 62 S2 members. Our high-resolution program provides α-elements (C, Mg, Si, Ca, and Ti), iron-peak elements (V, Cr, Mn, Fe, Ni), n-capture process elements (Sr, Ba), and other elements such as Li, Na, Al, and Sc for a subsample of S2 objects. We report coherent abundance patterns over a large metallicity spread (∼1 dex) confirming that the S2 stream was produced by a disrupted dwarf galaxy. The combination of S2's α-elements displays a mildly decreasing trend with increasing metallicity, which can be tentatively interpreted as a 'knee' at [Fe/H] < -2. At the low-metallicity end, the n-capture elements in S2 may be dominated by r-process production; however, several stars are Ba-enhanced but unusually poor in Sr. Moreover, some of the low-[Fe/H] stars appear to be carbon-enhanced. We interpret the observed abundance patterns with the help of chemical evolution models that demonstrate the need for modest star formation efficiency and low wind efficiency confirming that the progenitor of S2 was a primitive dwarf galaxy.

Abstract Copyright: © 2020 The Author(s) Published by Oxford University Press on behalf of the Royal Astronomical Society

Journal keyword(s): stars: abundances - Galaxy: evolution - Galaxy: formation - Galaxy: halo - Galaxy: kinematics and dynamics

Status at CDS : Large table(s) will be appraised for possible ingestion in VizieR.

Simbad objects: 38

goto Full paper

goto View the reference in ADS

To bookmark this query, right click on this link: simbad:2021MNRAS.500..889A and select 'bookmark this link' or equivalent in the popup menu


2021.04.12-17:30:27

© Université de Strasbourg/CNRS

    • Contact