Adding the s-Process Element Cerium to the APOGEE Survey: Identification and Characterization of Ce ii Lines in the H-band Spectral Window
Smith, Verne V.
Shetrone, Matthew D.
Allende Prieto, Carlos
García-Hernández, D. Anibal
Johnson, Jennifer A.
Majewski, Steven R.
Schiavon, Ricardo P.
Skrutskie, Michael F.
Fernández-Trincado, J. G.
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PublisherIOP PUBLISHING LTD
CitationAdding the s-Process Element Cerium to the APOGEE Survey: Identification and Characterization of Ce ii Lines in the H-band Spectral Window 2017, 844 (2):145 The Astrophysical Journal
JournalThe Astrophysical Journal
Rights© 2017. The American Astronomical Society. All rights reserved.
Collection InformationThis item from the UA Faculty Publications collection is made available by the University of Arizona with support from the University of Arizona Libraries. If you have questions, please contact us at firstname.lastname@example.org.
AbstractNine Ce II lines have been identified and characterized within the spectral window observed by the Apache Point Observatory Galactic Evolution Experiment (APOGEE) survey (between lambda 1.51 and 1.69 mu m). At solar metallicities, cerium is an element that is produced predominantly as a result of the slow capture of neutrons (the s-process) during asymptotic giant branch stellar evolution. The Ce II lines were identified using a combination of a high-resolution (R = lambda/delta lambda = 100,000) Fourier Transform Spectrometer (FTS) spectrum of a Boo and an APOGEE spectrum (R. =. 22,400) of a metal-poor, but s-process enriched, red giant (2M16011638-1201525). Laboratory oscillator strengths are not available for these lines. Astrophysical gf-values were derived using alpha Boo as a standard star, with the absolute cerium abundance in alpha Boo set by using optical Ce II lines that have precise published laboratory gf-values. The near-infrared Ce II lines identified here are also analyzed, as consistency checks, in a small number of bright red giants using archival FTS spectra, as well as a small sample of APOGEE red giants, including two members of the open cluster NGC 6819, two field stars, and seven metal-poor N-and Al-rich stars. The conclusion is that this set of Ce II lines can be detected and analyzed in a large fraction of the APOGEE red giant sample and will be useful for probing chemical evolution of the s-process products in various populations of the Milky Way.
VersionFinal published version
SponsorsNational Science Foundation [AST1109888]; Ramon y Cajal fellowship [RYC201314182]; Spanish Ministry of Economy and Competitiveness (MINECO) [AYA201458082-P]; Premium Postdoctoral Research Program of the Hungarian Academy of Sciences; Hungarian NKFI Grants of the Hungarian National Research, Development and Innovation Office [K-119517]; National Aeronautics and Space Administration; National Science Foundation; Spanish MINECO [AYA2014-56359-P]; Birgit and Hellmuth Hertz' Foundation; Royal Physiographic Society of Lund, Sweden; Alfred P. Sloan Foundation; U.S. Department of Energy Office of Science; High-Performance Computing at the University of Utah