Searching for R-process-enhanced Stars in the LAMOST Survey. II. Two New r-II Stars in the Milky Way Disk
Year: 2025
Type: article
Abstract: R-process-enhanced (RPE) stars are rare and typically metal-poor ([Fe/H] < −1.0), primarily found in the Milky Way halo system and dwarf galaxies. This study reports the discovery of two relatively bright, highly RPE stars ([Eu/Fe] > +0.70) located in the Milky Way disk, with [Fe/H] of −0.34 and −0.80, respectively. These two stars are selected from the Large Sky Area Multi-Object Fiber Spectroscopic Telescope medium-resolution (R ∼ 7500) spectroscopic survey. Follow-up high-resolution (R ∼ 25,000) observations were conducted with the High Optical Resolution Spectrograph installed on the 10.4 m Gran Telescopio Canarias. We perform the determination of elemental abundances and calculate the orbital parameters. We find that they are r-II stars with elemental abundances in agreement with the solar r-process pattern. These two objects are chemically and dynamically consistent with membership in the Galactic disk and exhibit no evidence of being part of accreted systems.
Source: The Astrophysical Journal
Institutions: Chinese Academy of Sciences, National Astronomical Observatories, University of Chinese Academy of Sciences, Nantong University, Beijing Normal University, Universidad de La Laguna, Instituto de Astrofísica de Canarias, University of Notre Dame, Institute of Modern Physics, Nanjing Institute of Astronomical Optics & Technology
Language: English
Subfield: Astronomy and Astrophysics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: gold
Estimated APC paid: $4,499
Funders: National Science Foundation, Joint Institute for Nuclear Astrophysics - Center for the Evolution of the Elements, Chinese Academy of Sciences, Youth Innovation Promotion Association of the Chinese Academy of Sciences, Ministerio de Ciencia e Innovación, National Development and Reform Commission, Instituto de Astrofísica de Canarias, National Astronomical Observatories, Chinese Academy of Sciences, Office of International Science and Engineering
OpenAlex ID: W4410189808