Chemical and Kinematic Analysis of CN-strong Metal-poor Field Stars in LAMOST DR3
Por:
Tang B., Liu C., Fernández-Trincado J.G., Geisler D., Shi J., Zamora O., Worthey G., Moreno E.
Publicada:
20 ene 2019
Resumen:
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 angstrom 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.
Filiaciones:
Tang B.:
Sun Yat Sen Univ, Sch Phys & Astron, Zhuhai 519082, Peoples R China
School of Physics and Astronomy, Sun Yat-sen University, Zhuhai, 519082, China
Liu C.:
Chinese Acad Sci, Key Lab Opt Astron, Natl Astron Observ, Beijing 100012, Peoples R China
Key Lab of Optical Astronomy, National Astronomical Observatories, Chinese Academy of Sciences, Beijing, 100012, China
Fernández-Trincado J.G.:
Univ Concepcion, Dept Astron, Casilla 160-C, Concepcion, Chile
Univ Bourgogne Franche Comte, CNRS UMR 6213, Inst Utinam, OSU THETA Franche Comte,Observ Besancon, BP 1615, F-25010 Besancon, France
Univ Atacama, Inst Astron & Ciencias Planetarias, Copayapu 485, Copiapo, Chile
Departamento de Astronomía, Universidad de Concepción, Casilla 160-C, Concepción, Chile
Institut Utinam, CNRS UMR 6213, Université Bourgogne-Franche-Comté, OSU THETA Franche-Comté, Observatoire de Besancon, BP 1615, Besancon, Cedex, F-25010, France
Instituto de Astronomía y Ciencias Planetarias, Universidad de Atacama, Copayapu 485, Copiapo, Chile
Geisler D.:
Univ Concepcion, Dept Astron, Casilla 160-C, Concepcion, Chile
Univ La Serena, Inst Invest Multidisciplinario Ciencia & Tecnol, Ave Raul Bitran S-N, La Serena, Chile
Univ La Serena, Fac Ciencias, Dept Fis & Astron, Ave Juan Cisternas 1200, La Serena, Chile
Departamento de Astronomía, Universidad de Concepción, Casilla 160-C, Concepción, Chile
Instituto de Investigación Multidisciplinario en Ciencia y Tecnologia, Universidad de la Serena, Avenida Raul Bitrán S/N, La Serena, Chile
Departamento de Fisica y Astronomia, Facultad de Ciencias, Universidad de la Serena, Av. Juan Cisternas, La Serena, 1200, Chile
Shi J.:
Chinese Acad Sci, Key Lab Opt Astron, Natl Astron Observ, Beijing 100012, Peoples R China
Key Lab of Optical Astronomy, National Astronomical Observatories, Chinese Academy of Sciences, Beijing, 100012, China
Zamora O.:
Inst Astrofis Canarias, E-38205 Tenerife, Spain
Univ La Laguna, Dept Astrofis, E-38206 Tenerife, Spain
Instituto de Astrofisica de Canarias, La Laguna, Tenerife, E-38205, Spain
Departamento de Astrofisica, Universidad de la Laguna, La Laguna, Tenerife, E-38206, Spain
Worthey G.:
Washington State Univ, Dept Phys & Astron, Pullman, WA 99163 USA
Department of Physics and Astronomy, Washington State University, Pullman, WA 99163-2814, United States
Moreno E.:
Univ Nacl Autonoma Mexico, Inst Astron, Apdo Postal 70264, Mexico City 04510, DF, Mexico
Instituto de Astronomia, Universidad Nacional Autónoma de México, Apdo. Postal 70264, México D.F., 04510, Mexico
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