Richard Scuflaire, Space Sciences, Technologies and Astrophysics Research (STAR) Institute, Université de Liège, 19C Allée du 6 Août, B-4000 Liège, Belgium
,
Arlette Noels, Space Sciences, Technologies and Astrophysics Research (STAR) Institute, Université de Liège, 19C Allée du 6 Août, B-4000 Liège, Belgium
In a series of papers, we have recently demonstrated that it is possible
to construct stellar structure models that robustly mimic the
stratification of multidimensional radiative magnetohydrodynamic
simulations at every time-step of the computed evolution. The resulting
models offer a more realistic depiction of the near-surface layers of
stars with convective envelopes than parametrizations, such as mixing
length theory, do. In this paper, we explore how this model improvement
impacts on seismic and non-seismic properties of stellar models across
the Hertzsprung-Russell diagram. We show that the improved description
of the outer boundary layers alters the predicted global stellar
properties at different evolutionary stages. In a hare and hound
exercise, we show that this plays a key role for asteroseismic analyses,
as it, for instance, often shifts the inferred stellar age estimates by
more than 10 per cent. Improper boundary conditions may thus introduce
systematic errors that exceed the required accuracy of the PLATO space
mission. Moreover, we discuss different approaches for computing stellar
oscillation frequencies. We demonstrate that the so-called gas
Γ1 approximation performs reasonably well for all
main-sequence stars. Using a Monte Carlo approach, we show that the
model frequencies of our hybrid solar models are consistent with
observations within the uncertainties of the global solar parameters
when using the so-called reduced Γ1 approximation.