From core to envelope: Revealing the deep dynamics of stars with two convective zones
Abstract
On the Hertzsprung-Russell diagram, F-type solar pulsators connect the Sun to intermediate-mass stars located on the instability strip. With respect to lower-mass stars, they are structurally peculiar in the sense that they are constituted of three distinct dynamical layers: a small convective core, a deep radiative interior, and a shallow convective envelope. Current asteroseismic techniques only provide limited information on the interior dynamics of these stars. Indeed only gravity modes ( g modes), for which unambiguous characterisation is lacking, are able to probe the deep stellar layers. A better understanding of the excitation and behaviour in F-type solar pulsators is therefore necessary in order to consider their detection. In this work, we simulate the global stellar structure of an F-type star (core, radiative interior, envelope) for the first time. We show that the contribution of the core strongly affects the spectrum of excited g modes, with low-order high-degree modes unable to form due to their interaction with the turbulent convection of the core. Finally, by computing the disc-integrated signature of the modes, we are able to demonstrate that they preserve their integrity up to the top of the convective envelope, which is a strong argument in favour of their detectability with space-borne photometry.
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BibTeX
@article{breton2026from,
title = {{From core to envelope: Revealing the deep dynamics of stars with two convective zones}},
author = {S N Breton and A S Brun and R A García},
journal = {Astronomy \& Astrophysics - A\&A},
year = {2026},
month = may,
doi = {10.1051/0004-6361/202659634},
url = {https://hal.science/hal-05740197v1},
note = {CC BY 4.0},
}
RIS
TY - JOUR
TI - From core to envelope: Revealing the deep dynamics of stars with two convective zones
AU - S N Breton
AU - A S Brun
AU - R A García
PY - 2026
DA - 2026/05/28
JO - Astronomy & Astrophysics - A&A
DO - 10.1051/0004-6361/202659634
UR - https://hal.science/hal-05740197v1
AB - On the Hertzsprung-Russell diagram, F-type solar pulsators connect the Sun to intermediate-mass stars located on the instability strip. With respect to lower-mass stars, they are structurally peculiar in the sense that they are constituted of three distinct dynamical layers: a small convective core, a deep radiative interior, and a shallow convective envelope. Current asteroseismic techniques only provide limited information on the interior dynamics of these stars. Indeed only gravity modes ( g modes), for which unambiguous characterisation is lacking, are able to probe the deep stellar layers. A better understanding of the excitation and behaviour in F-type solar pulsators is therefore necessary in order to consider their detection. In this work, we simulate the global stellar structure of an F-type star (core, radiative interior, envelope) for the first time. We show that the contribution of the core strongly affects the spectrum of excited g modes, with low-order high-degree modes unable to form due to their interaction with the turbulent convection of the core. Finally, by computing the disc-integrated signature of the modes, we are able to demonstrate that they preserve their integrity up to the top of the convective envelope, which is a strong argument in favour of their detectability with space-borne photometry.
SN - 0004-6361
SN - 1432-0746
ER -