Bibcode
Hasselquist, S.; Shetrone, Matthew; Cunha, Katia; Smith, Verne V.; Holtzman, Jon; Lawler, J. E.; Allende Prieto, C.; Beers, Timothy C.; Chojnowski, Drew; Fernández-Trincado, J. G.; García-Hernández, D. A.; Hearty, Fred R.; Majewski, Steven R.; Pereira, C. B.; Placco, Vinicius M.; Villanova, Sandro; Zamora, Olga
Bibliographical reference
The Astrophysical Journal, Volume 833, Issue 1, article id. 81, 7 pp. (2016).
Advertised on:
12
2016
Journal
Citations
60
Refereed citations
57
Description
We present the detection of 10 lines of singly ionized neodymium (Nd ii,
Z = 60) in H-band spectra using observations from the SDSS-III Apache
Point Observatory Galactic Evolution Experiment (APOGEE) survey. These
lines were detected in a metal-poor ([Fe/H] ∼ ‑1.5),
neutron-capture element-enhanced star recently discovered in the APOGEE
sample. Using an optical high-resolution spectrum, we derive a Nd
abundance for this star using Nd ii lines with precise,
laboratory-derived gf values. This optical abundance is used to derive
log(gf) values for the H-band lines. We use these lines to rederive Nd
ii abundances for two more metal-rich, s-process enhanced stars observed
by APOGEE and find that these lines yield consistent Nd ii abundances,
confirming the Nd enhancement of these stars. We explore the region of
parameter space in the APOGEE sample over which these lines can be used
to measure Nd ii abundances. We find that Nd abundances can be reliably
derived for ∼18% of the red giants observed by APOGEE. This will
result in ∼50,000 Milky Way stars with Nd ii abundances following
the conclusion of APOGEE-2, allowing for studies of neutron-capture
element abundance distributions across the entire Milky Way.