Facial reconstruction

Search LJMU Research Online

Browse Repository | Browse E-Theses

Adding the s-Process Element Cerium to the APOGEE Survey: Identification and Characterization of Ce II Lines in the H-band Spectral Window

Cunha, K, Smith, VV, Hasselquist, S, Souto, D, Shetrone, MD, Allende Prieto, C, Bizyaev, D, Frinchaboy, P, Anibal Garcia-Hernandez, D, Holtzman, J, Johnson, JA, Jonsson, H, Majewski, SR, Meszaros, S, Nidever, D, Pinsonneault, M, Schiavon, RP, Sobeck, J, Skrutskie, MF, Zamora, O , Zasowski, G and Fernandez-Trincado, JG (2017) Adding the s-Process Element Cerium to the APOGEE Survey: Identification and Characterization of Ce II Lines in the H-band Spectral Window. ASTROPHYSICAL JOURNAL, 844 (2). ISSN 0004-637X

[img]
Preview
Text
Cunha_2017_ApJ_844_145.pdf - Published Version

Download (827kB) | Preview

Abstract

Nine Ce ii lines have been identified and characterized within the spectral window observed by the Apache Point Observatory Galactic Evolution Experiment (APOGEE) survey (between λ1.51 and 1.69 μm). 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 ($R=\lambda /\delta \lambda ={\rm{100,000}}$) Fourier Transform Spectrometer (FTS) spectrum of α 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 α Boo as a standard star, with the absolute cerium abundance in α 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.

Item Type: Article
Uncontrolled Keywords: 0201 Astronomical And Space Sciences, 0305 Organic Chemistry, 0306 Physical Chemistry (Incl. Structural)
Subjects: Q Science > QB Astronomy
Divisions: Astrophysics Research Institute
Publisher: IOP PUBLISHING LTD
Related URLs:
Date Deposited: 02 Feb 2018 13:46
Last Modified: 02 Feb 2018 13:46
DOI or Identification number: 10.3847/1538-4357/aa7beb
URI: http://researchonline.ljmu.ac.uk/id/eprint/7933

Actions (login required)

View Item View Item