arXiv subjects

Stéphane Mathis

Publications and source records attributed to Stéphane Mathis.

At least 19 recordsLinked to original sources

arXiv2026

Asteroseismic imprints of strong non-axisymmetric fields in the cores of red giants

To date, magnetic fields have been asteroseismically measured in nearly one hundred red giant cores. However, most analyses assume weak magnetic fields and slow rotation so that perturbation theory can be applied. The "traditional approximation of rotation and magnetism" (TARM) method can predict gravity-mode frequencies under strong magnetic fields and rapid rotation rates. So far, this formalism requires the magnetic field to be symmetric about the rotation axis. We generalize the TARM formalism to apply to arbitrary magnetic field geometries, including cases where the magnetic and rotation axes are misaligned, as well as fields with no symmetry axis at all. The resulting gravity modes exhibit a rich diversity of wave behavior, including oblique pulsation and avoided crossings. We also clarify the domains of validity of perturbation theory and the TARM formalism.

astro-ph.SR↗

arXiv2026

Extending asteroseismic magnetometry across the diverse landscape of magnetic structures

Magnetic fields have now been asteroseismically measured in the cores of many red giants. However, most interpretations of these measurements assume that the magnetic field is far below the critical field strength known to be exceeded by red giants exhibiting gravity-mode suppression. A recent method based on the traditional approximation of rotation and magnetism accurately predicts mode frequencies under fields up to this critical value by modeling gravity waves as individual magnetogravity ``polarizations'' which propagate through a waveguide-like mode cavity. So far, this formalism has been limited to magnetic fields which are axisymmetric about the rotation axis. In this study, we extend this approach by calculating the polarizations of magnetogravity waves under arbitrarily shaped magnetic fields under potentially rapid rotation. We consider the special cases of a dipolar magnetic field misaligned with the rotation axis as well as a dipole-plus-quadrupole magnetic field with no rotational symmetry. We show that non-axisymmetric field configurations can induce avoided crossings between polarizations, and that waves in such systems can convert between magnetogravity polarizations as they propagate, especially when the magnetic field strength is locally below a stratification-dependent threshold value. This threshold is distinct from the critical field strength for gravity-mode suppression, and is instead similar to the magnetic field strength at which perturbation theory breaks down.

astro-ph.SR↗

arXiv2026

Hidden worlds: A non-transiting candidate planet in the Neptunian desert around the solar-type pulsator KIC 9139163

Close-in substellar companions experience strong tidal and magnetic interactions with their host stars and are therefore subject to fast orbital evolution. The solar-type pulsator KIC 9139163 exhibits in its light curve a stable 0.6-day modulation for which the best explanation is the presence of a close-in non-transiting companion that we therefore attempt to characterise. We combine Kepler and TESS photometric data with spectroscopic observations obtained with HARPS-N. The analysis of the radial velocities obtained with HARPS-N provides a companion mass $M_p \sin i = 7.3 \pm 1.4 \, \mathrm{M}_{\oplus}$. We infer a planetary radius of $2.43 \pm 0.14 \, \mathrm{R}_\oplus$, which, combined with the measured mass and retrieved inclination, implies a bulk density consistent with a hot water-rich world. This places the non-transiting companion candidate of KIC 9139163 within the Neptunian desert, a regime where planets are expected either to have lost their primordial hydrogen/helium envelopes or to harbour metal-enriched atmospheres. We further detect significant variations in amplitude between the Kepler and TESS phase curves, obtained six years apart, as well as a secular increase in amplitude over the Kepler baseline. Our fit favours a model with two distinct longitudinal cloud offsets over a single-offset scenario. Both datasets indicate a moderate-to-high geometric albedo and low-to-moderate heat redistribution. The opposite phase offsets observed in the Kepler and TESS datasets suggest a time-variable longitudinal brightness distribution. While making KIC 9139163 an interesting candidate for future ground follow-ups, it also suggests that searching for other non-transiting planets around fast stellar rotators in space-borne photometric surveys might provide new insights into the physics of the Neptunian planets located in the desert. [shortened]

astro-ph.EP↗

arXiv2026

Understanding hydrodynamical wave-driven shear mixing in stellar radiation zones. Looking in the mirror of the dyapicnal oceanic mixing

Stellar radiation zones play a key role in the long-term magneto-rotational and chemical evolution of stars. As parts of the oceans and of the atmosphere of the Earth, their dynamics is controlled by the Archimedean buoyancy force and the Coriolis acceleration. They are the seat of an efficient extraction of angular momentum and of a mild mixing of chemicals. In this context, particle tracing in recent nonlinear hydrodynamical equatorial numerical simulations of stellar radiation zones where internal gravity waves (hereafter IGWs) are propagating led to the measurement of an effective diffusivity following the prescriptions derived by Garcia-Lopez & Spruit and by Zahn for the inflectional instability of the vertical shear of low-frequency IGWs. However, the associated instability criteria are not fullfiled. This effective diffusivity is found to scale as the squared velocity of IGWs for every rotation rates. Other dependences have also been derived in the literature, for instance in the case of the Stokes displacement. To interpret these results, we propose to explore the parameterisation for the mixing of particles, which has been proposed for the oceans. A foundation stone in physical oceanography is the so-called Osborn & Cox energetic balance that leads to an effective dyapicnal diffusivity for the transport of matter that scales as the ratio of the dissipation of the fluctuating flows over the squared Brunt-V\"ais\"al\"a stratification frequency. We demonstrate that this diffusivity is equivalent to the eddy diffusivity derived by Zahn for the inflectional instability of the vertical shear applied to low-frequency IGWs. This allows us to characterize the corresponding energetic balance where the power extracted by the waves from the mean flows is balanced by their dissipation and by the power produced by their buoyancy flux, which triggers mixing, for any rotation rate.

astro-ph.SR↗

arXiv2026

Twists in the flow: revisiting convective mixing in rotating stellar models. I. Effect on the stellar structure

Convection and rotation are both key processes in stellar evolution modelling. While standard mixing-length theory (MLT) provides a widely used modelling of convection, it neglects the effects of rotation on convective transport. We investigate how rotating mixing-length theory (R-MLT), which accounts for the influence of rotation on convection, affects the internal structure, convective mixing, and angular momentum transport in stellar models in comparison to the standard non-rotating MLT. Using the MESA stellar structure and evolution software, we model the main-sequence evolution of a 5 M$_{\odot}$ star, for three cases: non-rotating, rotating with standard MLT for modelling convection, and rotating with R-MLT in convection zones, with the initial rotation rate set to 20 percent of the critical (Keplerian) value at the surface for the rotating models. We find that R-MLT reduces both the convective velocity and mixing length in the stellar core, leading to a smaller convective diffusion coefficient and about 20 percent reduction in the extent of the convective overshooting region. While the overall size of the convective core remains nearly unchanged, R-MLT changes the resulting chemical gradient at the core-envelope boundary, shifting the peak of the Brunt-V\"ais\"al\"a frequency and modifying the angular momentum transport in that region. Including the effects of rotation in the treatment of convection through R-MLT introduces measurable structural and transport differences, underscoring the importance of incorporating rotation-convection coupling in models of stars.

astro-ph.SR↗

arXiv2026

Core-envelope coupling of gravito-inertial waves in pre-main-sequence solar-type stars

After the recent detection of solar equatorial Rossby waves, a renewed interest has been brought to the study of gravito-inertial waves propagating in the convective envelope of solar-type stars. In particular, the ability that some of these envelope gravito-inertial modes have to couple with the ones trapped in the radiative interior might open new windows to probe the deep-layer dynamics of solar-type stars. The possibility for such a coupling to occur is particularly favoured in pre-main sequence (PMS) solar-type stars. Indeed, due to the contraction of the protostellar object, they are able to reach large rotation frequencies before nuclear reactions are ignited and magnetic braking becomes the driving mechanism for their rotational evolution. In this work, we therefore study the coupling between the envelope inertial waves and the radiative interior g modes in PMS stars, focusing on the case of prograde dipolar modes. We consider the case of 0.5 Msun and 1 Msun PMS models, each with three different scenarios of rotational evolution. We show that, for stars that have formed with a sufficient amount of angular momentum, this coupling can occur in frequency ranges that are accessible to space-borne photometry, creating inertial dips in the period spacing pattern. With an asymptotic analysis we characterise the shape of these inertial dips to show that they depend on rotation and on the stiffness of the convective-radiative interface.

astro-ph.SR↗

arXiv2026

Impact of rotation on the amplitude of acoustic modes in solar-like stars: Insights from hydrodynamical simulations

In solar-like stars, acoustic modes provide the main way of probing their internal structure and dynamics. Although these modes are expected to be ubiquitous in stars with convective envelopes, Kepler observations reveal that a significant fraction of solar-like stars show no detectable acoustic modes, particularly among rapidly rotating and magnetically active stars. Recent theoretical work has proposed that rotation tends to inhibit convective motions, thereby reducing the power available for stochastic excitation of low degree acoustic modes. Here, we test this prediction using fully compressible hydrodynamical simulations of a solar-like star. We perform a series of 2.5D simulations, which consider longitudinal symmetry, using the MUSIC code spanning rotation rates from 0 to 8 $\Omega_{\odot}$. We find a clear and systematic decline of acoustic mode amplitudes with increasing rotation rate. In the most rapidly rotating models, mode damping rates are also enhanced. The combined reduction in excitation and increase in damping with increasing rotation rate provide a physical explanation for the observed decrease in mode detectability in rapidly rotating solar-like stars. Our results demonstrate that rotation can significantly modify oscillation properties and must be accounted for when interpreting asteroseismic observations.

astro-ph.SR↗

arXiv2025

Evidence for the Keplerian orbit of a close companion around a giant star

Close companions influence stellar evolution through tidal interactions, mass transfer, and mass loss effects. While such companions are detected around young stellar objects, main-sequence stars, red giants, and compact objects, direct observational evidence of close-in companions around asymptotic giant branch (AGB) stars has remained elusive. Here, we present (sub)millimeter time-domain imaging spectroscopy revealing the Keplerian motion of a close-in companion around the AGB star pi1 Gruis. The companion, slightly more massive than the AGB star, is likely a main-sequence star. Unlike more evolved stars with companions at comparable distances, pi1 Gru's companion follows a circular orbit, suggesting an eccentricity-generating mechanism late- or post-AGB. Our analysis suggests that model-predicted circularization rates may be underestimated. Our results highlight the potential of multi-epoch (sub)millimeter interferometry in detecting the Keplerian motion of close companions to giant stars and open avenues for our understanding of tidal interaction physics and binary evolution.

astro-ph.SR↗

arXiv2025

Parametrisation of the wave-zonal flow interactions taking into account the full Coriolis acceleration. The necessity of going beyond the traditional approximation in the sub-inertial regime and in weakly stratified regions

From the Earth's atmosphere and oceans to stellar radiation zones, inertia-gravity waves, which are called gravito-inertial waves (hereafter GIWs) in Astrophysics, are transporting momentum and mixing matter when they are damped through heat and viscous diffusions and when they break. Their short-time scale dynamics is governed by the buoyancy force and the Coriolis acceleration. Because of the transport they trigger, they modify the long-term evolution of the large-scale planetary atmospheric (oceanic) circulation and of the structure and rotation of stars. In many state-of-the-art models, the so-called Traditional Approximation of Rotation (hereafter denoted TAR), where the local projection of the rotation vector along the horizontal direction is neglected, is assumed. We aim to identify the applicability regime of this approximation and to propose a non-traditional parametrisation of wave - zonal flow interactions, in which the full Coriolis acceleration is taken into account. We build a prototype local non-traditional Cartesian model in which we take into account the full Coriolis acceleration, buoyancy, and heat and viscous diffusions. On the one hand, the TAR is strongly underestimating GIWs damping in the sub-inertial regime. In this regime a non-traditional modelling must be adopted to predict the correct altitude where momentum is deposited, which is closer to the excitation region of waves than the one predicted using the TAR. On the other hand, non-traditional modellings of GIWs convective and shear-induced breakings are proposed. Taking into account the full Coriolis acceleration leads to a stronger inhibition of the efficiency of the convective and shear-induced overturnings and to a weaker transport than those predicted when assuming the TAR. Finally, a fully non-traditional parametrisation of GIWs - mean zonal flows interaction is derived.

astro-ph.SR↗

arXiv2025

Non-linear evolution of the horizontal shear instability in stratified rotating fluids under the complete Coriolis acceleration

This paper investigates the non-linear dynamics of horizontal shear instability in an incompressible, stratified and rotating fluid in the non-traditional $f$-plane, i.e. with the full Coriolis acceleration, using direct numerical simulations. The study is restricted to two-dimensional horizontal perturbations. It is therefore independent of the vertical (traditional) Coriolis parameter. However, the flow has three velocity components due to the horizontal (non-traditional) Coriolis parameter. Three different scenarios of non-linear evolution of the shear instability are identified, depending on the non-dimensional Brunt-V\"ais\"al\"a frequency $N$ and the non-dimensional non-traditional Coriolis parameter $\tilde{f}$ (non-dimensionalized by the maximum shear), in the range $\tilde{f}<N$ for fixed Reynolds and Schmidt numbers $Re=2000$, $Sc=1$. When the stratification is strong $N\gg 1$, the shear instability generates stable Kelvin-Helmholtz billows like in the traditional limit $\tilde{f}=0$. Furthermore, when $N\gg1$, the governing equations for any $\tilde{f}$ can be transformed into those for $\tilde{f}=0$. This enables us to directly predict the characteristics of the flow depending on $\tilde{f}$ and $N$. When $N$ is around unity and $\tilde{f}$ is above a threshold, the primary Kelvin-Helmholtz vortex is destabilised by secondary instabilities but it remains coherent. For weaker stratification, $N\leqslant0.5$ and $\tilde{f}$ large enough, secondary instabilities develop vigorously and destroy the primary vortex into small-scales turbulence. Concomitantly, the enstrophy rises to high values by stretching/tilting as in fully three-dimensional flows. A local analysis of the flow prior to the onset of secondary instabilities reveals that the Fjortoft necessary condition for instability is satisfied, suggesting that they correspond to shear instabilities.

physics.flu-dyn↗

arXiv2025

Exploring hydrodynamical stellar tachoclines along stellar evolution

Stellar tachoclines are thin regions located between the radiative core and the convective envelope of solar-type stars. They are defined as layers where the rotation of the radiative interior transitions to the differential rotation of the convective envelope, generating strong shear and turbulence. As such, understanding the dynamics of the transport and mixing inside stellar tachoclines would shed light on how the dynamical processes of the convection zone might affect the secular transport of the radiative zone. In particular, we investigate how the change of the latitudinal differential rotation in the convection zone with stellar evolution would affect the dynamics of the tachocline. Indeed, as solar-type stars are braked on the Main Sequence, the differential rotation in the convection zone is expected to evolve from a cylindrical rapidly-rotating regime (columns of varying velocities, aligned with the rotation axis) to a conical solar-like regime (with an equatorial acceleration as in the case of the Sun) and finally to a conical anti-solar-like regime (with a polar acceleration). However, stellar evolutionary codes currently only consider at best the solar conical regime to study the dynamics of stellar tachoclines throughout the evolution of stars. We discuss different possibilities to model hydrodynamical tachoclines and we show that Mathis Zahn 2004's formalism is able to treat coherently hydrodynamical stellar tachoclines when taken in the thin layer approximation. We use it to model the differential rotation, meridional circulation, and mixing coefficients inside the tachocline in order to examine the effect of the different rotation regimes on the transport.

astro-ph.SR↗

arXiv2025

The inertial dip as a window on the convective core dynamics

Gamma Dor stars are ideal targets for studies of the innermost dynamical properties of stars, due to their rich frequency spectrum of gravito-inertial modes propagating in the radiative envelope. Recent studies found that these modes could couple at the core-to-envelope interface with pure inertial modes in their sub-inertial regime, forming the so-called inertial dip in the period-spacing pattern of these stars. The inertial dip, as formed by core modes, stands out as a unique probe of core properties. We aim in this work to explore the effect of core magnetism on its structure, property of key relevance in modern stellar physics. We describe the outlines of our model and the geometry of the considered field. We give the coupling equation and the variation of the dip shape and location with increasing magnetic contrast between the core and the envelope. We compare our findings to the ones obtained in a hydrodynamical, differentially-rotating case. We show hints at potentially lifting the degeneracy between the signatures of core-to-envelope differential rotation and core magnetic fields. Together, these two cases can be considered as an exploration of different magnetic regimes potentially reached in the core of gamma Dor stars.

astro-ph.SR↗

arXiv2025

The impact of differential rotation on the stochastic excitation of acoustic modes in solar-like pulsators

Acoustic modes are excited by turbulent convection in the outer convective envelope of solar-like stars. Observational results from asteroseismic studies show that 44% of solar-like stars do not present detectable stochastically-excited acoustic modes. This phenomenon appears to be related to their rotation rate and magnetic activity. In a first paper, we showed that uniform rotation tends to diminish the mode amplitudes significantly. However, convective envelopes in solar-type stars are differentially rotating: the rotation rate difference between mid-latitudes and the equator can go up to 60%, as shown by recent asteroseismic works. In this paper, we examine the impact of differential rotation on the stochastic excitation of acoustic modes in solar-like stars. We provide theoretical predictions for the excitation of acoustic modes in a differentially rotating solar-like star. We use the Rotating Mixing-Length Theory approach to model the local influence of differential rotation on convection. We then estimate the resulting impact on power injection by turbulent convection into oscillation modes numerically, using a combination of the MESA stellar structure and evolution code and GYRE stellar pulsation code. We show that the power injected in acoustic modes differs by up to 30 % for stars with the same mean rotation rate $5 \Omega_{\odot}$ but a distinct differential rotation rate. The excitation of axisymmetric acoustic modes is further inhibited in the anti-solar differential rotation regime where the pole of stars rotates faster than their equator when compared to the uniform rotation case. This could hinder mode detection in such configurations. This study permits a first prediction of the excitation of acoustic modes as a function of the differential rotation in solar-like pulsators.

astro-ph.SR↗

arXiv2025

Exploring the probing power of gamma-Dor's inertial dip for core magnetism: case of a toroidal field

Gamma-Dor stars are ideal targets for studies of stellar innermost dynamical properties due to their rich asteroseismic spectrum of gravity modes. Integrating internal magnetism to the picture appears as the next milestone of detailed asteroseismic studies, for its prime importance on stellar evolution. The inertial dip in prograde dipole modes period-spacing pattern of gamma-Dors stands out as a unique window on the convective core structure and dynamics. Recent studies have highlighted the dependence of the dip structure on core density stratification, contrast of the near-core Brunt-V\"ais\"al\"a frequency and rotation rate, as well as the core-to-near-core differential rotation. In the meantime, the effect of magnetism has been derived on envelope modes. We aim to revisit the inertial dip formation including core and envelope magnetism, and explore the probing power of this feature on dynamo-generated core fields. We consider a toroidal magnetic field with a bi-layer (core and envelope) Alfv\'en frequency. This configuration allows us to revisit the coupling problem using our knowledge on both core magneto-inertial modes and envelope magneto-gravito-inertial modes. We stay in an analytical framework to exhibit the magnetic effects on the inertial dip shape and location, setting up a laboratory towards the comprehension of magnetic effects on the dip structure. We show a shift of the inertial dip towards lower spin parameter values and a thinner dip with increasing core magnetic field, quite similar to the signature of differential rotation. The magnetic effects become sizeable when the ratio between the magnetic and the Coriolis effects is large enough. We explore the degeneracy of the magnetic effects with differential rotation. We study the detectability of core magnetism, considering observational constraints on the modes periods and potential gravito-inertial mode suppression.

astro-ph.SR↗

arXiv2025

A model of magnetised and rotating convection for stellar and planetary interiors

Convection is a fundamental mechanism for energy transport in stars and planets, playing a pivotal role in shaping their structures and evolution. The Mixing-Length Theory, a monomodal approach to convection, is widely adopted and implemented in 1D stellar structure and evolution codes. However, it overlooks the combined effects of rotation and magnetic fields, which are ubiquitous across a wide range of stars and planets. To address this limitation, we extend the Mixing-Length Theory including both rotation and magnetic fields within a Cartesian set-up. Building on the work by Stevenson 1979, we use a heat-flux maximisation principle, which amounts to selecting the convective mode that carries the most heat. Our findings show that both rotation and magnetic fields individually tend to suppress convection. However, when combined, they can enhance convection strength under certain conditions. We derive expressions for the root-mean-square (rms) velocity, characteristic length scale, and degree of superadiabaticity as functions of the rotation rate and magnetic field strength. These results offer new insights for more accurately modeling convection and its impact on stellar and planetary structures in one-dimensional and forthcoming multi-dimensional evolution models.

astro-ph.SR↗

arXiv2025

Magnetic activity evolution of solar-like stars: II. $S_{\rm ph}$-Ro evolution of Kepler main-sequence targets

There is now a large sample of stars observed by the Kepler satellite with measured rotation periods and photometric activity index $S_{\rm ph}$. We use this data, in conjunction with stellar interiors models, to explore the interplay of magnetism, rotation, and convection. Stellar activity proxies other than $S_{\rm ph}$ are correlated with the Rossby number, $Ro$, or ratio of rotation period to convective overturn timescale. We compute the latter using the Yale Rotating Evolution Code stellar models. We observe different $S_{\rm ph}$-$Ro$ relationships for different stellar spectral types. Though the overall trend of decreasing magnetic activity versus $Ro$ is recovered, we find a localized dip in $S_{\rm ph}$ around $Ro/Ro_{\odot} \sim$\,0.3 for the G and K dwarfs. F dwarfs show little to no dependence of $S_{\rm ph}$ on $Ro$ due to their shallow convective zones; further accentuated as $T_{\rm eff}$ increases. The dip in activity for the G and K dwarfs corresponds to the intermediate rotation period gap, suggesting that the dip in $S_{\rm ph}$ could be associated with the redistribution of angular momentum between the core and convective envelope inside stars. For G-type stars, we observe enhanced magnetic activity above solar $Ro$. Compared to other Sun-like stars with similar effective temperature and metallicity, we find that the Sun's current level of magnetic activity is comparable to its peers and lies near the transition to increasing magnetic activity at high $Ro$. We confirm that metal-rich stars have a systematically larger $S_{\rm ph}$ level than metal-poor stars, which is likely a consequence of their deeper convective zones.

astro-ph.SR↗

arXiv2025

Vertical shear instabilities in rotating stellar radiation zones: effects of the full Coriolis acceleration and thermal diffusion

Rotation deeply impacts the structure and the evolution of stars. To build coherent 1D or multi-D stellar structure and evolution models, we must systematically evaluate the turbulent transport of momentum and matter induced by hydrodynamical instabilities of radial and latitudinal differential rotation in stably stratified thermally diffusive stellar radiation zones. In this work, we investigate vertical shear instabilities in these regions. The full Coriolis acceleration with the complete rotation vector at a general latitude is taken into account. We formulate the problem by considering a canonical shear flow with a hyperbolic-tangent profile. We perform linear stability analysis on this base flow using both numerical and asymptotic Wentzel-Kramers-Brillouin-Jeffreys (WKBJ) methods. Two types of instabilities are identified and explored: inflectional instability, which occurs in the presence of an inflection point in shear flow, and inertial instability due to an imbalance between the centrifugal acceleration and pressure gradient. Both instabilities are promoted as thermal diffusion becomes stronger or stratification becomes weaker. Effects of the full Coriolis acceleration are found to be more complex according to parametric investigations in wide ranges of colatitudes and rotation-to-shear and rotation-to-stratification ratios. Also, new prescriptions for the vertical eddy viscosity are derived to model the turbulent transport triggered by each instability. We foresee that the inflectional instability will be responsible for turbulent transport in the equatorial region of strongly-stratified radiative zones in slowly rotating stars while the inertial instability triggers turbulence in the polar regions of weakly-stratified radiative zones in fast-rotating stars.

astro-ph.SR↗

arXiv2024

The impact of rotation on the stochastic excitation of stellar acoustic modes in solar-like pulsators

Recent observational results from asteroseismic studies show that an important fraction of solar-like stars do not present detectable stochastically excited acoustic oscillations. This non-detectability seems to correlate with a high rotation rate in the convective envelope and a high surface magnetic activity. At the same time, the properties of stellar convection are affected by rotation and magnetism. We investigate the role of rotation in the excitation of acoustic modes in the convective envelope of solar-like stars, to evaluate its impact on the energy injected in the oscillations. We derive theoretical prescriptions for the excitation of acoustic waves in the convective envelope of rotating solar-like stars. We adopt the Rotating Mixing-Length Theory to model the influence of rotation on convection. We use the MESA stellar evolution code and the GYRE stellar oscillation code to estimate the power injected in the oscillations from our theoretical prescriptions. We demonstrate that the power injected in the acoustic modes is insensitive to the rotation if a Gaussian time-correlation function is assumed, while it can decrease by up to 60 % for a Lorentzian time-correlation function, for a $20 \Omega_{\odot}$ rotation rate. This result can allow us to better constrain the properties of stellar convection by studying observationally acoustic modes excitation. These results demonstrate how important it is to take into account the modification of stellar convection by rotation when evaluating the amplitude of the stellar oscillations it stochastically excites. They open the path for understanding the large variety of observed acoustic-mode amplitudes at the surface of solar-like stars as a function of surface rotation rates.

astro-ph.SR↗