2026A&A...706L..19B

Asteroseismology is widely used for the precise mass determination of solar-like oscillating stars, based on individual frequency modeling or homological scaling relations. However, these methods have not been dynamically validated on the main sequence (MS) due to the absence of eclipsing double-lined binary system (SB2) as benchmark objects. By providing the orbital inclination, astrometric binary systems from ESA Gaia DR3 offer an abundant alternative for eclipsing systems. We present KIC 9693187 as the first SB2 hosting a solar-like oscillating post-MS star with dynamical masses. By combining Gaia astrometry with spectroscopic data obtained with the Las Cumbres Observatory network (LCO), we found M₁^dyn = 0.99 ± 0.05 M_⊙ and M₂^dyn = 0.89 ± 0.04 M_⊙ for the primary and secondary, respectively. The asteroseismic parameters were extracted from photometry of the NASA Kepler satellite. The mass from individual frequency modeling is M₁^IF = 0.92 ± 0.01 M_⊙. Taking into account the systematic uncertainty of 0.04 M_⊙ for best-fit models from individual frequency fitting, we found an agreement within 1.2σ. From the scaling relations, we obtained a mass range of 0.93 to 0.98 M_⊙ by using the observed large frequency separations (Δν) in the scaling relations for the primary. By using standard corrections for departures from the asymptotic regime of Δν, we obtained a mass range of 0.83 to 1.03 M_⊙. The upper ends of both ranges agree well with the dynamical mass of the primary. This approach provides the first empirical validation for MS solar-like oscillators and opens a new window for validating the asteroseismology. Through a dedicated program targeting astrometric SB2 binary systems, ESA's PLATO space mission will effectively enlarge the benchmark sample to a considerable extent.