Abundances of Rarely Detected s-process Elements Derived from the Ultraviolet Spectrum of the s-process-enhanced Metal-poor Star HD 196944

Fuente: arXiv
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Main Authors: Roederer, Ian U., Placco, Vinicius M., Karakas, Amanda I., Hartog, Elizabeth A. Den, Beers, Timothy C.
Format: Preprint
Published: 2025
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author Roederer, Ian U.
Placco, Vinicius M.
Karakas, Amanda I.
Hartog, Elizabeth A. Den
Beers, Timothy C.
author_facet Roederer, Ian U.
Placco, Vinicius M.
Karakas, Amanda I.
Hartog, Elizabeth A. Den
Beers, Timothy C.
contents We present an analysis of the heavy-element abundances of HD 196944, a carbon-enhanced metal-poor (CEMP) star enriched with elements produced by the slow neutron-capture process (s-process). We obtained a new high-resolution ultraviolet (UV) spectrum of this star, the UV-brightest known CEMP-s star, with the Space Telescope Imaging Spectrograph on board the Hubble Space Telescope. This spectrum extends deeper into the UV (2029 < lambda < 2303 Angstroms) than previous studies of any CEMP-s star. When combined with previous UV and optical analysis, a total of 35 elements heavier than zinc (Z = 30) can be detected in HD 196944, and upper limits are available for nine other heavy elements. The abundances can be well fit by models of s-process nucleosynthesis operating in a low-mass companion star that evolved through the asymptotic giant branch phase and transferred heavy elements to HD 196944. This s-process event did not contribute substantially to the Ga, Ge, or As abundances (31 <= Z <= 33). Our results demonstrate that UV spectroscopy can greatly expand the inventory of heavy elements detectable in CEMP-s stars.
format Preprint
id arxiv_https___arxiv_org_abs_2510_11922
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Abundances of Rarely Detected s-process Elements Derived from the Ultraviolet Spectrum of the s-process-enhanced Metal-poor Star HD 196944
Roederer, Ian U.
Placco, Vinicius M.
Karakas, Amanda I.
Hartog, Elizabeth A. Den
Beers, Timothy C.
Solar and Stellar Astrophysics
We present an analysis of the heavy-element abundances of HD 196944, a carbon-enhanced metal-poor (CEMP) star enriched with elements produced by the slow neutron-capture process (s-process). We obtained a new high-resolution ultraviolet (UV) spectrum of this star, the UV-brightest known CEMP-s star, with the Space Telescope Imaging Spectrograph on board the Hubble Space Telescope. This spectrum extends deeper into the UV (2029 < lambda < 2303 Angstroms) than previous studies of any CEMP-s star. When combined with previous UV and optical analysis, a total of 35 elements heavier than zinc (Z = 30) can be detected in HD 196944, and upper limits are available for nine other heavy elements. The abundances can be well fit by models of s-process nucleosynthesis operating in a low-mass companion star that evolved through the asymptotic giant branch phase and transferred heavy elements to HD 196944. This s-process event did not contribute substantially to the Ga, Ge, or As abundances (31 <= Z <= 33). Our results demonstrate that UV spectroscopy can greatly expand the inventory of heavy elements detectable in CEMP-s stars.
title Abundances of Rarely Detected s-process Elements Derived from the Ultraviolet Spectrum of the s-process-enhanced Metal-poor Star HD 196944
topic Solar and Stellar Astrophysics
url https://arxiv.org/abs/2510.11922