Bibcode
Tang, B.; Liu, Chao; Fernández-Trincado, J. G.; Geisler, Doug; Shi, Jianrong; Zamora, O.; Worthey, Guy; Moreno, Edmundo
Bibliographical reference
The Astrophysical Journal, Volume 871, Issue 1, article id. 58, 13 pp. (2019).
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1
2019
Journal
Citations
24
Refereed citations
24
Description
The large amount of chemical and kinematic information available in
large spectroscopic surveys has inspired the search for chemically
peculiar stars in the field. Though these metal-poor field stars ([Fe/H]
<‑1) are commonly enriched in nitrogen, their detailed
spatial, kinematic, and chemical distributions suggest that various
groups may exist, and thus their origin is still a mystery. To study
these stars statistically, we increase the sample size by identifying
new CN-strong stars with LAMOST DR3 for the first time. We use
CN–CH bands around 4000 Å to find CN-strong stars, and
further separate them into CH-normal stars (44) and CH-strong (or CH)
stars (35). The chemical abundances from our data-driven software and
APOGEE DR14 suggest that most CH-normal stars are N-rich, and this
cannot be explained by an internal mixing process alone. The kinematics
of our CH-normal stars indicate that a substantial fraction of these
stars are retrograding, pointing to an extragalactic origin. The
chemistry and kinematics of CH-normal stars imply that they may be stars
dissolved from globular clusters, or accreted halo stars, or both.
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Nucleosynthesis and molecular processes in the late stages of Stellar Evolution
Low- to intermediate-mass (M < 8 solar masses, Ms) stars represent the majority of stars in the Cosmos. They finish their lives on the Asymptotic Giant Branch (AGB) - just before they form planetary nebulae (PNe) - where they experience complex nucleosynthetic and molecular processes. AGB stars are important contributors to the enrichment of the
Domingo Aníbal
García Hernández