Stellar Models are Reliable at Low Metallicity: An Asteroseismic Age for the Ancient Very Metal-poor Star KIC 8144907
Abstract Very-metal-poor stars ([Fe/H] < −2) are important laboratories for testing stellar models and reconstructing the formation history of our galaxy. Asteroseismology is a powerful tool to probe stellar interiors and measure ages, but few asteroseismic detections are known in very-metal-poor stars and none have allowed detailed modeling of oscillation frequencies. We report the discovery of a low-luminosity Kepler red giant (KIC 8144907) with high signal-to-noise ratio oscillations, [Fe/H] = −2.66 ± 0.08 and [ α /Fe] = 0.38 ± 0.06, making it by far the most metal-poor star to date for which detailed asteroseismic modeling is possible. By combining the oscillation spectrum from Kepler with high-resolution spectroscopy, we measure an asteroseismic mass and age of 0.79 ± 0.02(ran) ± 0.01(sys) M ⊙ and 12.0 ± 0.6(ran) ± 0.4(sys) Gyr, with remarkable agreement across different codes and input physics, demonstrating that stellar models and asteroseismology are reliable for very-metal-poor stars when individual frequencies are used. The results also provide a direct age anchor for the early formation of the Milky Way, implying that substantial star formation did not commence until redshift z ≈ 3 (if the star formed in situ) or that the Milky Way has undergone merger events for at least ≈12 Gyr (if the star was accreted by a dwarf satellite merger such as Gaia-Enceladus).
Authors
- Michael Greklek-McKeon (ORCID: https://orcid.org/0000-0002-0371-1647)
- Meridith Joyce (ORCID: https://orcid.org/0000-0002-8717-127X)
- J. M. Joel Ong (ORCID: https://orcid.org/0000-0001-7664-648X)
- Evan N. Kirby (ORCID: https://orcid.org/0000-0001-6196-5162)
- Dennis Stello (ORCID: https://orcid.org/0000-0002-4879-3519)
- Daniel Huber (ORCID: https://orcid.org/0000-0001-8832-4488)
- Travis A. Berger (ORCID: https://orcid.org/0000-0002-2580-3614)
- V. Silva Aguirre (ORCID: https://orcid.org/0000-0002-6137-903X)
- Teruyuki Hirano (ORCID: https://orcid.org/0000-0003-3618-7535)
- T. R. Bedding (ORCID: https://orcid.org/0000-0001-5222-4661)
- Arthur Alencastro Puls
- Aldo Serenelli (ORCID: https://orcid.org/0000-0001-6359-2769)
- D. Slumstrup (ORCID: https://orcid.org/0000-0003-4538-9518)
- Marc H. Pinsonneault (ORCID: https://orcid.org/0000-0002-7549-7766)
- Joel Zinn (ORCID: https://orcid.org/0000-0002-7550-7151)
- Samuel K. Grunblatt (ORCID: https://orcid.org/0000-0003-4976-9980)
- Marc Hon (ORCID: https://orcid.org/0000-0003-2400-6960)
- Yaguang Li (ORCID: https://orcid.org/0000-0003-3020-4437)
Institutions
- Ruhr University Bochum (DE)
Publication Details
- Journal
- The Astrophysical Journal
- Published
- 2024-10-23
- DOI
- https://doi.org/10.3847/1538-4357/ad7110
- Citations
- 12
- Primary Topic
- Stellar, planetary, and galactic studies
- Type
- article
- Field-Weighted Citation Impact
- 3.98
Funders
- National Science Foundation
- National Aeronautics and Space Administration
- Alfred P. Sloan Foundation
- W. M. Keck Foundation
- California Institute of Technology
- European Commission
- Deutsche Forschungsgemeinschaft
- Generalitat de Catalunya
- Nuclear Safety and Security Commission
- National Astronomical Observatory of Japan
- NASA Headquarters