Element abundance analysis of the metal-rich stellar halo and high-velocitythick disk in the galaxy

TL;DR

This study uses Gaia DR2 and APOGEE DR16 data to analyze element abundances in high-velocity thick disk and metal-rich stellar halo stars, revealing their possible origins and chemical similarities.

Contribution

It introduces a multidimensional data processing algorithm for chemical abundance analysis, providing insights into the origins of different stellar populations.

Findings

Some HVTD stars may originate from the thin disk.

Some MRSH stars may come from dwarf galaxies.

Stars with similar chemical characteristics may form in-situ.

Abstract

Based on the second Gaia data release (DR2) and APOGEE (DR16) spectroscopic surveys, wedefined two kinds of star sample: high-velocity thick disk (HVTD) with $v{\phi}>90km/s$ and metal-richstellar halo (MRSH) with $v{\phi}<90km/s$. Due to high resolution spectra data from APOGEE (DR16),we can analyze accurately the element abundance distribution of HVTD and MRSH. These elementsabundance constituted a multidimensional data space, and we introduced an algorithm method forprocessing multi-dimensional data to give the result of dimensionality reduction clustering. Accordingto chemical properties analysis, we derived that some HVTD stars could origin from the thin disk,and some MRSH stars from dwarf galaxies, but those stars which have similar chemical abundancecharacteristics in both sample may form in-situ.