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The R-process Alliance: The Peculiar Chemical Abundance Pattern of RAVE J183013.5-455510
Name
Placco_2020_ApJ_897_78.pdf
Description
Published version
Size
10.9 MB
Format
Adobe PDF
Checksum (MD5)
a47600c5aca94aa6c626ab50f0c7f821
Author(s)
Placco, VM
Santucci, RM
Yuan, Z
Mardini, MK
Holmbeck, EM
Wang, X
Surman, R
Hansen, TT
Roederer, IU
Beers, TC
Journal
Astrophysical Journal
Publisher
American Astronomical Society
Version
Final published version
Abstract
© 2020. The American Astronomical Society. All rights reserved. We report on the spectroscopic analysis of RAVE J183013.5-455510, an extremely metal-poor star, highly enhanced in CNO, and with discernible contributions from the rapid neutron-capture process. There is no evidence of binarity for this object. At =-3.57, this star has one of the lowest metallicities currently observed, with 18 measured abundances of neutron-capture elements. The presence of Ba, La, and Ce abundances above the solar system r-process predictions suggests that there must have been a non-standard source of r-process elements operating at such low metallicities. One plausible explanation is that this enhancement originates from material ejected at unusually high velocities in a neutron star merger event. We also explore the possibility that the neutron-capture elements were produced during the evolution and explosion of a rotating massive star. In addition, based on comparisons with yields from zero-metallicity faint supernova, we speculate that RAVE J1830-4555 was formed from a gas cloud pre-enriched by both progenitor types. From analysis based on Gaia DR2 measurements, we show that this star has orbital properties similar to the Galactic metal-weak thick-disk stellar population.
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DOI of Published Version
10.3847/1538-4357/ab99c6
