![Activity-age relationship for solar-type stars from Pezzotti et al. (2026). HD 219134 is denoted by the green square. Kepler LEGACY data from Pezzotti et al. (2026) are shown as cyan dots, Booth et al. (2017) data are indicated by salmon pentagons, and the Sun is shown by a black circled dot. The black lines indicate the linear fit from Booth et al. (2017) (dashed line) and Pezzotti et al. (2026) (dotted line). -- [astro-ph.EP]](https://i0.wp.com/astrobiology.com/wp-content/uploads/2026/10/Detailed.png?fit=1200%2C674&ssl=1)
[astro-ph.EP] Space missions such as CoRoT, Kepler, and TESS have transformed asteroseismology and its synergies with exoplanet science.
We revisit the nearby K-dwarf HD 219134 to investigate the tension between asteroseismic and interferometric radii, update its fundamental parameters, and reconstruct the rotational, magnetic, and atmospheric evolution of the system.
We combine forward asteroseismic modeling with seismic inversions to assess systematics from non-seismic constraints, radius measurements, and surface modeling. The revised stellar properties are then used for rotational evolution, stellar-wind, and high-energy irradiation calculations.
Seismic inversions rule out the most recent interferometric radius, while the asteroseismic and spectroscopic results are compatible with the 2019 interferometric measurement. We obtain M=0.779±0.015(stat)±0.006(sys) M⊙, R=0.753±0.005(stat)±0.002(sys) R⊙, and an age of 8.92±0.89(stat)±0.19(sys) Gyr.
These systematics include only non-seismic constraints; literature combined uncertainties from physical inputs and surface effects are 0.007M⊙, 0.002R⊙, and 0.81 Gyr. Rotational and wind modelling shows that standard magnetic braking is broadly compatible with the present-day rotation and angular-momentum loss. Weakened braking gives a closer match but challenges standard wind-loss scalings.
The inferred X-ray history suggests early stripping of the innermost planets, while the outer planets likely retained part of their primordial envelopes; HD 219134d experienced only moderate erosion. The apparent radius discrepancy likely reflects underestimated uncertainties in previous interferometric analyses rather than an astrophysical inconsistency.
We advocate adopting the asteroseismic radius, which is robust to modeling assumptions and optimisation strategies.
Jérôme Bétrisey, Camilla Pezzotti, Gaël Buldgen, Aline A. Vidotto, Colin P. Folsom, Michaël De Becker, Michaël Gillon
Comments: Accepted for publication in Astronomy and Astrophysics
Subjects: Earth and Planetary Astrophysics (astro-ph.EP); Solar and Stellar Astrophysics (astro-ph.SR)
Cite as: arXiv:2610.13200 [astro-ph.EP](or arXiv:2610.13200v1 [astro-ph.EP] for this version)
https://doi.org/10.48550/arXiv.2610.13200
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Submission history
From: Jérôme Bétrisey
[v1] Fri, 9 Oct 2026 08:19:27 UTC (4,747 KB)
https://arxiv.org/abs/2610.13200
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