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Related papers: Discovery of an Extremely r-process-enhanced Thin-…

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Object LAMOST J020623.21+494127.9 (program star) in the thin disk of the Milky Way (MW) is reported as a highly r-process-enhanced (RPE) r-II star with[Eu/Fe]= +1.32 and [Fe/H]= -0.54. The chemical profile of the star reflects the intrinsic…

Solar and Stellar Astrophysics · Physics 2025-05-13 Muhammad Zeshan Ashraf , Wenyuan Cui , Hongjie Li

A high-resolution spectroscopic analysis is presented for a new highly r-process-enhanced ([Eu/Fe] = 1.27, [Ba/Eu] = -0.65), very metal-poor ([Fe/H] = -2.09), retrograde halo star, RAVE J153830.9-180424, discovered as part of the R-Process…

We present a detailed chemical-abundance analysis of a highly $r$-process enhanced (RPE) star, 2MASS J00512646-1053170, using high-resolution spectroscopic observations with $Hubble\ Space\ Telescope$/STIS in the UV and Magellan/MIKE in the…

The abundance patterns of $r$-process-enhanced stars contain key information required to constrain the astrophysical site(s) of $r$-process nucleosynthesis, and to deepen our understanding of the chemical evolution of our Galaxy. In order…

Solar and Stellar Astrophysics · Physics 2021-03-31 Tian-Yi Chen , Jian-Rong Shi , Timothy C. Beers , Hong-Liang Yan , Qi Gao , Chun-Qian Li , Hai-Ning Li , Gang Zhao

We report the discovery of an extremely metal-poor (EMP) giant, LAMOST J110901.22+075441.8, which exhibits large excess of r-process elements with [Eu/Fe] ~ +1.16. The star is one of the newly discovered EMP stars identified from LAMOST…

Solar and Stellar Astrophysics · Physics 2015-06-18 Haining Li , Wako Aoki , Satoshi Honda , Gang Zhao , Norbert Christlieb , Takuma Suda

We present a detailed abundance analysis of the bright (V = 9.02), metal-poor ([Fe/H] = -1.47 +/- 0.08) field red horizontal-branch star HD 222925, which was observed as part of an ongoing survey by the R-Process Alliance. We calculate…

Solar and Stellar Astrophysics · Physics 2018-10-17 Ian U. Roederer , Charli M. Sakari , Vinicius M. Placco , Timothy C. Beers , Rana Ezzeddine , Anna Frebel , Terese T. Hansen

We report the discovery of a cool metal-poor, main-sequence star exhibiting large excesses of r-process elements. This star is one of two newly discovered cool subdwarfs (effective temperatures of 5000 K) with extremely low metallicity…

Solar and Stellar Astrophysics · Physics 2015-05-20 Wako Aoki , Timothy C. Beer , Satoshi Honda , Daniela Carollo

We report the discovery of nine metal-poor stars with high levels of r-process enhancement (+0.81<[Eu/Fe]<+1.13), including six subgiants and three stars on the red horizontal branch. We also analyze four previously-known r-process-enhanced…

Solar and Stellar Astrophysics · Physics 2015-06-22 Ian U. Roederer , John J. Cowan , George W. Preston , Stephen A. Shectman , Chris Sneden , Ian B. Thompson

A new moderately r-process-enhanced metal-poor star, RAVE J093730.5-062655, has been identified in the Milky Way halo as part of an ongoing survey by the R-Process Alliance. The temperature and surface gravity indicate that J0937-0626 is…

We present and discuss three extremely r-process enhanced stars located in the massive dwarf spheriodal galaxy Fornax. These stars are very unique with an extreme Eu enrichment ($1.25\le \mathrm{[Eu/Fe]} \le 1.45$) at high metallicities…

Astrophysics of Galaxies · Physics 2021-05-26 M. Reichert , C. J. Hansen , A. Arcones

We present stellar parameters and chemical abundances of 47 elements detected in the bright (V = 11.63) very metal-poor ([Fe/H] = -2.20 +- 0.12) star 2MASS J22132050-5137385. We observed this star using the Magellan Inamori Kyocera Echelle…

We report the discovery of J1521-3538, a bright (V=12.2), very metal-poor ([Fe/H]=-2.8) strongly r-process enhanced field horizontal branch star, based on a high-resolution, high signal-to-noise Magellan/MIKE spectrum. J1521-3538 shows the…

Aims. Stars with strong enhancements of r-process elements are rare and tend to be metal-poor, with generally [Fe/H] <-2 dex and found in the halo. In this work we aim to investigate a candidate r-process enriched bulge star with a…

Solar and Stellar Astrophysics · Physics 2022-12-28 R. Forsberg , R. M. Rich , N. Nieuwmunster , H. Jönsson , M. Schultheis , N. Ryde , B. Thorsbro

We present detailed chemical abundances of three new bright (V ~ 11), extremely metal-poor ([Fe/H] ~ -3.0), r-process-enhanced halo red giants based on high-resolution, high-S/N Magellan/MIKE spectra. We measured abundances for 20-25…

The recent detection of a binary neutron star merger and the clear evidence for the decay of radioactive material observed in this event have, after sixty years of effort, provided an astrophysical site for the rapid neutron-capture ($r$-)…

We have obtained high-resolution (R $\simeq$ 50,000 or 90,000), high-quality (S/N $\ga$ 100) spectra of 22 very metal-poor stars ([Fe/H] $\la$ -2.5) with the High Dispersion Spectrograph fabricated for the 8.2m Subaru Telescope. The spectra…

We report the discovery of RAVE J203843.2-002333, a bright (V = 12.73), very metal-poor ([Fe/H] = -2.91), r-process-enhanced ([Eu/Fe] = +1.64 and [Ba/Eu] = -0.81) star selected from the RAVE survey. This star was identified as a metal-poor…

A few rare halo giants in the range [Fe/H] $\simeq -2.9\pm0.3$ exhibit {\it r}-process element abundances that vary as a group by factors up to [$r$/Fe] $\sim80$, relative to those of the iron peak and below. Yet, the astrophysical…

Astrophysics of Galaxies · Physics 2015-05-30 Terese Hansen , Johannes Andersen , Birgitta Nordström , Lars A. Buchhave , Timothy C. Beers

We present a nearly complete rapid neutron-capture process (r-process) chemical inventory of the metal-poor ([Fe/H] = -1.46 +/- 0.10) r-process-enhanced ([Eu/Fe] = +1.32 +/- 0.08) halo star HD 222925. This abundance set is the most complete…

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