Details

Autor(en) / Beteiligte

• Roederer, Ian U.
• Cowan, John J.
• Pignatari, Marco
• Beers, Timothy C.
• Den Hartog, Elizabeth A.
• Ezzeddine, Rana
• Frebel, Anna
• Hansen, Terese T.
• Holmbeck, Erika M.
• Mumpower, Matthew R.
• Placco, Vinicius M.
• Sakari, Charli M.
• Surman, Rebecca
• Vassh, Nicole

Titel

The R-Process Alliance: Abundance Universality among Some Elements at and between the First and Second R-Process Peaks

Ist Teil von

• The Astrophysical journal, 2022-09, Vol.936 (1), p.84

Ort / Verlag

Philadelphia: IOP Publishing

Erscheinungsjahr

2022

Quelle

EZB Electronic Journals Library

Beschreibungen/Notizen

• Abstract We present new observational benchmarks of rapid neutron-capture process ( r -process) nucleosynthesis for elements at and between the first ( A ∼ 80) and second ( A ∼ 130) peaks. Our analysis is based on archival ultraviolet and optical spectroscopy of eight metal-poor stars with Se ( Z = 34) or Te ( Z = 52) detections, whose r -process enhancement varies by more than a factor of 30 (−0.22 ≤ [Eu/Fe] ≤ +1.32). We calculate ratios among the abundances of Se, Sr through Mo (38 ≤ Z ≤ 42), and Te. These benchmarks may offer a new empirical alternative to the predicted solar system r -process residual pattern. The Te abundances in these stars correlate more closely with the lighter r -process elements than the heavier ones, contradicting and superseding previous findings. The small star-to-star dispersion among the abundances of Se, Sr, Y, Zr, Nb, Mo, and Te (≤0.13 dex, or 26%) matches that observed among the abundances of the lanthanides and third r -process-peak elements. The concept of r -process universality that is recognized among the lanthanide and third-peak elements in r -process-enhanced stars may also apply to Se, Sr, Y, Zr, Nb, Mo, and Te, provided the overall abundances of the lighter r -process elements are scaled independently of the heavier ones. The abundance behavior of the elements Ru through Sn (44 ≤ Z ≤ 50) requires further study. Our results suggest that at least one relatively common source in the early Universe produced a consistent abundance pattern among some elements spanning the first and second r -process peaks.