Discovery of a Metal-poor Red Giant Star with the Highest Ultralithium Enhancement
Year: 2024
Type: article
Abstract: We present the discovery of 2MASS J05241392−0336543 (hereafter J0524−0336), a very metal-poor ([Fe/H] = −2.43 ± 0.16), highly r -process-enhanced ([Eu/Fe] = +1.34 ± 0.10) Milky Way halo field red giant star, with an ultrahigh Li abundance of A (Li, 3D, NLTE) = 6.15 ± 0.25 and [Li/Fe] = +7.64 ± 0.25, respectively. This makes J0524−0336 the most lithium-enhanced giant star discovered to date. We present a detailed analysis of the star’s atmospheric stellar parameters and chemical abundance determinations. Additionally, we detect indications of infrared excess, as well as observe variable emission in the wings of the H α absorption line across multiple epochs, indicative of a potential enhanced mass-loss event with possible outflows. Our analysis reveals that J0524−0336 lies either between the bump and the tip of the red giant branch (RGB), or on the early asymptotic giant branch (e-AGB). We investigate the possible sources of lithium enrichment in J0524−0336, including both internal and external sources. Based on current models and on the observational evidence we have collected, our study shows that J0524−0336 may be undergoing the so-called lithium flash that is expected to occur in low-mass stars when they reach the RGB bump and/or the e-AGB.
Source: The Astrophysical Journal
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, National Aeronautics and Space Administration, National Computational Infrastructure, Australian Government, Joint Institute for Nuclear Astrophysics - Center for the Evolution of the Elements, European Space Agency, Schweizerischer Nationalfonds zur Förderung der Wissenschaftlichen Forschung, Nuclear Safety and Security Commission, Vetenskapsrådet, Center for Undergraduate Research and Scholarship, Bowling Green State University, National Cancer Institute, Astrophysics Division
Awards: JINA Center for the Evolution of the Elements, G2695431083, A New Vision on Globular Cluster Archeology, Establishing the Properties of the First Stars and Supernovae and the Origins of the Heaviest Elements with Stellar Archaeology, G425872791, Collaborative Research: Galactic Archaeology from Careful Modeling of Old Stars, G5599649393, The making of the heaviest elements in the Universe, Collaborative Research: Dwarf Galaxies Over Cosmic Time, G628552264, Collaborative Research: Dark Matter and Substructure in the Galactic Halo with Gaia and Multi-Object Spectroscopy, Collaborative Research: Dark Matter and Substructure in the Galactic Halo with Gaia and Multi-Object Spectroscopy, G7844045020
OpenAlex ID: W4402886639