Cookies

We use cookies to ensure that we give you the best experience on our website. By continuing to browse this repository, you give consent for essential cookies to be used. You can read more about our Privacy and Cookie Policy.


Durham Research Online
You are in:

The detailed chemical abundance patterns of accreted halo stars from the optical to infrared

Carrillo, Andreia and Hawkins, Keith and Jofré, Paula and de Brito Silva, Danielle and Das, Payel and Lucey, Madeline (2022) 'The detailed chemical abundance patterns of accreted halo stars from the optical to infrared.', Monthly Notices of the Royal Astronomical Society, 513 (2). pp. 1557-1580.

Abstract

Understanding the assembly of our Galaxy requires us to also characterize the systems that helped build it. In this work, we accomplish this by exploring the chemistry of accreted halo stars from Gaia-Enceladus/Gaia-Sausage (GES) selected in the infrared from the Apache Point Observatory Galactic Evolution Experiment (APOGEE) Data Release 16. We use high resolution optical spectra for 62 GES stars to measure abundances in 20 elements spanning the α, Fe-peak, light, odd-Z, and notably, the neutron-capture groups of elements to understand their trends in the context of and in contrast to the Milky Way and other stellar populations. Using these derived abundances we find that the optical and the infrared abundances agree to within 0.15 dex except for O, Co, Na, Cu, and Ce. These stars have enhanced neutron-capture abundance trends compared to the Milky Way, and their [Eu/Mg] and neutron-capture abundance ratios (e.g. [Y/Eu], [Ba/Eu], [Zr/Ba], [La/Ba], and [Nd/Ba]) point to r-process enhancement and a delay in s-process enrichment. Their [α/Fe] trend is lower than the Milky Way trend for [Fe/H] > −1.5 dex, similar to previous studies of GES stars and consistent with the picture that these stars formed in a system with a lower rate of star formation. This is further supported by their depleted abundances in Ni, Na, and Cu abundances, again, similar to previous studies of low-α stars with accreted origins.

Item Type:Article
Full text:(VoR) Version of Record
Download PDF
(3479Kb)
Status:Peer-reviewed
Publisher Web site:https://doi.org/10.1093/mnras/stac518
Publisher statement:This article has been accepted for publication in Monthly notices of the Royal Astronomical Society. ©: 2021 The Author(s). Published by Oxford University Press on behalf of the Royal Astronomical Society. All rights reserved.
Date accepted:21 February 2022
Date deposited:23 June 2022
Date of first online publication:28 April 2022
Date first made open access:23 June 2022

Save or Share this output

Export:
Export
Look up in GoogleScholar