TY - JOUR
T1 - Chemodynamical Analysis of Metal-rich High-eccentricity Stars in the Milky Way's Disk
AU - Lee, Ayeon
AU - Lee, Young Sun
AU - Kim, Young Kwang
AU - Beers, Timothy C.
AU - An, Deokkeun
N1 - Publisher Copyright:
© 2023. The Author(s). Published by the American Astronomical Society.
PY - 2023/3/1
Y1 - 2023/3/1
N2 - We present a chemodynamical analysis of 11,562 metal-rich, high-eccentricity halo-like main-sequence stars, which have been referred to as the Splash or Splashed Disk, selected from the Sloan Digital Sky Survey and Large Sky Area Multi-Object Fiber Spectroscopic Telescope. When divided into two groups, a low-[α/Fe] population (LAP) and a high-[α/Fe] population (HAP), based on kinematics and chemistry, we find that they exhibit very distinct properties, indicative of different origins. From a detailed analysis of their orbital inclinations, we suggest that the HAP arises from a large fraction (∼90%) of heated disk stars and a small fraction (∼10%) of in situ stars from a starburst population, likely induced by interaction of the Milky Way with the Gaia-Sausage/Enceladus (GSE) or another early merger. The LAP comprises about half accreted stars from the GSE and half formed by the GSE-induced starburst. Our findings further imply that the Splash stars in our sample originated from at least three different mechanisms: accretion, disk heating, and a merger-induced starburst.
AB - We present a chemodynamical analysis of 11,562 metal-rich, high-eccentricity halo-like main-sequence stars, which have been referred to as the Splash or Splashed Disk, selected from the Sloan Digital Sky Survey and Large Sky Area Multi-Object Fiber Spectroscopic Telescope. When divided into two groups, a low-[α/Fe] population (LAP) and a high-[α/Fe] population (HAP), based on kinematics and chemistry, we find that they exhibit very distinct properties, indicative of different origins. From a detailed analysis of their orbital inclinations, we suggest that the HAP arises from a large fraction (∼90%) of heated disk stars and a small fraction (∼10%) of in situ stars from a starburst population, likely induced by interaction of the Milky Way with the Gaia-Sausage/Enceladus (GSE) or another early merger. The LAP comprises about half accreted stars from the GSE and half formed by the GSE-induced starburst. Our findings further imply that the Splash stars in our sample originated from at least three different mechanisms: accretion, disk heating, and a merger-induced starburst.
UR - http://www.scopus.com/inward/record.url?scp=85150807171&partnerID=8YFLogxK
U2 - 10.3847/1538-4357/acb6f5
DO - 10.3847/1538-4357/acb6f5
M3 - Article
AN - SCOPUS:85150807171
SN - 0004-637X
VL - 945
JO - Astrophysical Journal
JF - Astrophysical Journal
IS - 1
M1 - 56
ER -