Evolved Stars with Inconsistent Age Estimates: Abundance Outliers or Mass Transfer Products?
Year: 2026
Type: article
Abstract: In the Milky Way disk, there is a strong trend linking stellar age to surface element abundances. Here, we explore this relationship with a data set of 8803 red-giant and red-clump stars with both asteroseismic data from NASA Kepler Mission and surface abundances from the Sloan Digital Sky Survey (SDSS)-V Milky Way Mapper (MWM) survey. We find, with a k -nearest-neighbors approach, that the [Mg/H] and [Fe/Mg] abundance ratios predict asteroseismic ages to an accuracy of about 2 Gyr for the majority of stars. That said, there are substantial outlier stars whose surface abundances do not match their asteroseismic ages. Because asteroseismic ages for these stars are fundamentally based on density or mass, these outliers are mass-transfer candidates. Stars whose surface abundances predict an older age (lower mass) than what’s seen in the asteroseismology are mass accretor candidates (MACs); stars whose abundances predict a younger age (higher mass) than the asteroseismology age are mass donor candidates (MDCs). We create precise control samples, matched according to (1) surface abundances and (2) asteroseismic ages, for both the MAC and MDC stars; we use these to find slight differences in rotational velocity, [C/N], and [Na/Mg] between the mass-transfer candidates and their abundance neighbors. We find no drastic differences in kinematics, orbital invariants, UV excess, or other stellar abundances between outliers and their abundance neighbors. We deliver 377 mass-transfer candidates for follow-up observations. This project implicitly suggests a fundamental limit on the reliability of asteroseismic ages, and supports existing evidence that age-abundance outliers are products of binary mass transfer.
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, Alfred P. Sloan Foundation, Yale University, Carnegie Institution of Washington, Ohio State University, California Institute of Technology, Harvard University, Johns Hopkins University, New Mexico State University, Space Telescope Science Institute, European Space Agency, Flatiron Health, École Polytechnique Fédérale de Lausanne, University of Toronto, Universidad Nacional Autónoma de México, Yunnan University, Nanjing University, China National Textile and Apparel Council, Leibniz-Institut für Astrophysik Potsdam, Max-Planck-Institut für Astronomie, University of Illinois at Urbana-Champaign, University of Colorado Boulder, Smithsonian Astrophysical Observatory, Science Mission Directorate, Leibniz-Gemeinschaft, National Astronomical Observatories, Chinese Academy of Sciences
OpenAlex ID: W4415913039