KIC 4150611: A quadruply eclipsing heptuple star system with a g -mode period-spacing pattern: Asteroseismic modelling of the g -mode period-spacing pattern

• Published in: Astronomy and astrophysics (Berlin) 2025-01, Vol.693, p.A184
• Main Authors: Kemp, Alex, Fritzewski, Dario J., Van Reeth, Timothy, IJspeert, Luc, Michielsen, Mathias, Mombarg, Joey S. G., Vanlaer, Vincent, Li, Gang, Tkachenko, Andrew, Aerts, Conny
• Format: Article
• Language: English
• ISSN: 0004-6361; 1432-0746
• DOI: 10.1051/0004-6361/202451995

Context. KIC 4150611 is a high-order (seventh-order) multiple composed of a triple system with: a F1V primary (Aa), which is eclipsed on a 94.2 d period by a tight binary composed of two K/M dwarfs (Ab1 and Ab2) that also eclipse each other; an eccentric, eclipsing binary composed of two G stars (Ba and Bb); and another faint eclipsing binary composed of two stars of unknown spectral type (Ca and Cb). In addition to its many eclipses, the system is an triple-lined spectroscopic multiple (Aa, Ba, and Bb) and the primary (Aa) is a hybrid pulsator that exhibits high amplitude pressure and gravity modes ( g -modes). Furthermore, its g -modes are arrayed in a period-spacing pattern, which greatly assists with mode identification and asteroseismic modelling. In aggregate, this richness in physics offers an excellent opportunity to obtain a precise physical characterisation for some of the stars in this system. Aims. In this work we estimate the stellar parameters of the primary (Aa) by performing asteroseismic analysis on its period-spacing pattern. Methods. We used the C-3PO neural network to perform asteroseismic modelling of the g -mode period-spacing pattern of Aa, examining the interplay of this information with external constraints from spectroscopy ( T eff and log( g )) and eclipse modelling ( R ). To estimate the level of uncertainty due to different frequency extraction and pattern identification processes, we considered four different variations of the period-spacing patterns. To better understand the correlations between and the uncertainty structure of our parameter estimates, we also employed a classical, parameter-based Markov chain Monte Carlo (MCMC) grid search on four different stellar grids. Results. The externally constrained model that best fits the period-spacing pattern arrives at estimates of the stellar properties for Aa of M = 1.51 ± 0.05 M ⊙ , X c = 0.43 ± 0.04, R = 1.66 ± 0.1 R ⊙ , f ov = 0.010, Ω c = 1.58 ± 0.01 d −1 with rigid rotation to within the measurement errors, log( T eff ) = 3.856 ± 0.008 dex, log( g ) = 4.18 ± 0.04 dex, and log( L ) = 0.809 ± 0.005 dex, which agree well with previous measurements from eclipse modelling, spectroscopy, and the Gaia DR3 luminosity. Conclusions. We find that the near-core properties of the best-fitting asteroseismic models are consistent with external constraints from eclipse modelling and spectroscopy. For stellar properties not related to the near-core region, external constraints on the aste